Jesus has given us the mission of being His witnesses to the ends of the earth.
Bible Study Ideas and Commentary for Acts 1
In this densely-packed introduction to the book of Acts, we learn how Jesus set the mission of the church -- to witness to His salvation to the ends of the earth, set the tone of the church -- to be as self-sacrificing as He was, and set the urgency for the church -- one day, Jesus is returning, and history will end. This is the foundation for the early Christian church.
and you will be my witnesses (1:8)
We Studied Acts in 2016/2018
I know, that was a while ago. Here's my post from those days:
I will bring this up a few times below.
Getting Started: Things to Think About
The Scariest Decision You've Made
Getting married? Taking a new job? Moving across country? Having a child? What was that decision for you and how did you go about making it?
In this week's passage, we read about the first of a whole series of scary decisions the early Christians made. Once they realized that God was their power and guide, it ceased to be all that scary...
How Do You Prepare for a Trip?
Maybe this is going on vacation. Maybe it's moving to a new house. Maybe it's moving to a new office. What kind of a planner are you for a trip like that? How many t's do you need crossed before you are comfortable? How many contingencies do you plan for?
In this week's passage, we see the early Christians facing the greatest adventure ever. We will see the plans they made (that they knew to make), and we will see the things they left to God. God calls each one of us to follow Him into an unknown future, and we will all do so according to our personality. All I can encourage you with is that you need to trust in God's ability to sustain you more than your ability to prepare.
Doing Your Homework before Making a Decision
This is a variation of that first idea. When you're about to make a big decision, how do you go about making it? What kind of research do you do? Who do you talk to?
Like with the previous topic, my encouragement is that we need to make sure that we never trust our research more than we trust God's leadership.
Why Is It Helpful to Know Your Church's History?
First Baptist Thomson actually has an official published history book. Not many churches have that. But you don't have to have a published book to have a way of learning your church's history.
Why should any church care to remember its history? Yes, there's the "learning from mistakes" thing. But it's also a way to know "why did we build this building the way we did?" or "why does this classroom have this stuff in it?" or "who was instrumental in getting this ministry off the ground?" and things like that.
For a person who has lived through it, it might not be a big deal. But for a person coming like (like, say, a new pastor), that information is invaluable.
Luke wrote his history of the church so new people coming could know (1) why the church came about in the first place, (2) who the important early leaders were and what they taught, and (3) the purpose and mission Jesus gave to the church. Our church's purpose and mission are one and the same with theirs, but every church has a unique expression of that.
Introducing the Book of Acts
When We Studied Acts in 2016/2018
My post for the first lesson in Acts back in 2016 focused on introducing the book -- author, date, purpose, with a focus on Luke; I will cover all of those things again below. I also gave an overview of the controversies surrounding the book.
My Topical Outline for the Quarter
This is just for your information. There are so many critical topics covered in this book that we couldn't hope to cover them all in any one week. This is my outline. If, when you read my notes, you wonder why I haven't covered something more in depth, it might be because I plan to address it later this quarter.
June 2: Acts 1:4-11, 23-26 -- introduction to Acts, state of world missions
June 9: Acts 2:5-6, 36-38 -- Pentecost, the Holy Spirit
June 16: Acts 2:41-47 -- the purpose of the church
June 23: Acts 3:12-26 -- the message of the church
June 30: Acts 4:8-21 -- church and culture
July 7: Acts 4:36-5:11 -- giving, accountability
July 14: Acts 5:29-42 -- persecution
July 21: Acts 6:1-15 -- serving, Stephen, deacons
July 28: Acts 8:26-39 -- baptism
August 4: Acts 9:3-16 -- Paul
August 11: Acts 9:32-43 -- the miraculous gifts
August 18: Acts 10:34-48 -- multigenerational, multicultural
August 25: Acts 12:6-18 -- Peter
The Bible Project's Resources for Luke/Acts
I shouldn't have to remind you how valuable these free resources are. The Bible Project has two different series covering the book of Acts. The more narrative-driven one puts Acts in the context of the Gospel of Luke, which is "Part 1" of Luke's grander Luke-Acts narrative (see below). This series offers four videos on Acts, divided into the traditional outline of the book. Here are the first two:
You can see the entire series on their website:
The Bible Project also has a more in-depth study of how the book of Acts is put together. Acts is so long that they divide it into two videos:
Standard Outlines of the Book of Acts
There are a lot of ways to approach the book of Acts. Here's the outline that Lifeway will follow:
The Church Empowered (Acts 1:1-2:47)
The Church's Early Days (Acts 3:1-12:25)
Paul's First Missionary Journey (Acts 13:1-14:28)
The Jerusalem Council (Acts 15:1-35)
Paul's Second Missionary Journey (Acts 15:36-18:22)
Paul's Third Missionary Journey (Acts 18:23-21:16)
Paul's Arrest and Journey to Rome (Acts 21:17-28:31)
Here's the simplified outline from the Bible Project:
Acts 1: Jesus Commissions His Disciples and Ascends to Heaven
Acts 2-7: Pentecost in Jerusalem and the Birth of the Church
Acts 8-12: The Jesus Community Becomes an International Movement
Acts 13-20: Mission to Israel and Clashes with Roman Culture
Acts 21-28: Paul Arrested in Jerusalem and Imprisoned in Rome
Here's the simplified outline from the NIV Study Bible:
The Spirit Empowers the Church for Witness (1:1-2:47)
The Apostolic Witness in Jerusalem (3:1-5:42)
The Witness beyond Jerusalem (6:1-12:24)
The Witness to the Ends of the Earth (12:25-28:31)
And here's the simplified outline from the Expositor's Bible Commentary:
Introduction: The Constitutive Events of the Christian Mission (1:1-2:41)
The Christian Mission to the Jewish World (2:42-12:24)
Panel 1: The Earliest Days of the Church at Jerusalem (2:42-6:7)
Panel 2: Critical Events in the Lives of Three Pivotal Figures (6:8-9:31)
Panel 3: Advances of the Gospel in Palestine-Syria (9:32-12:24)
The Christian Mission to the Gentile World (12:25-28:31)
Panel 4: The First Missionary Journey and the Jerusalem Council (12:25-16:5)
Panel 5: Wide Outreach through Two Missionary Journeys (16:6-19:20)
Panel 6: To Jerusalem and then to Rome (19:21-28:31)
You can see similarities and differences between those outlines. Why are they different? People who study the Bible outline the individual books to help them identify the main points they think the author was trying to make. For example, you can probably tell from the NIV Study Bible outline that they think the book was intended to demonstrate the progression of "Jerusalem" to "Judea/Samaria" to "the end of the earth". And I think that's a wise way to read the book of Acts!
Personally, I prefer the outline from the Expositor's Bible Commentary. They identified a series of "summary verses" (like 6:7 -- "so the Word of God spread...") throughout the book and believe that Luke put those verses in those places to give structure to his book. In particular, they see the parallels between the emphasis on Peter's ministry in the first part of Acts and the emphasis on Paul's ministry in the second part of Acts. I think they're right (more on this below) (and they still emphasize the progress from Jerusalem to the ends of the earth).
About Acts: The Author
The author does not identify himself. However, there is no one with Christian credibility who doesn't think that the same person who wrote the Gospel of Luke also wrote the book of Acts. The language, the style, and the structure are too similar to call that into question, especially since the author of Acts mentions a previous work about Jesus!
Luke 1: 1 Many have undertaken to compile a narrative about the events that have been fulfilled among us, 2 just as the original eyewitnesses and servants of the word handed them down to us. 3 So it also seemed good to me, since I have carefully investigated everything from the very first, to write to you in an orderly sequence, most honorable Theophilus, 4 so that you may know the certainty of the things about which you have been instructed.
Acts 1: 1 I wrote the first narrative, Theophilus, about all that Jesus began to do and teach 2 until the day he was taken up, after he had given instructions through the Holy Spirit to the apostles he had chosen. 3 After he had suffered, he also presented himself alive to them by many convincing proofs, appearing to them over a period of forty days and speaking about the kingdom of God.
Traditionally, the author of Luke has been identified as, er, Luke. In fact, no one has credibly suggested someone different! Luke is identified via 3 passages:
Col 4:14 Luke, the dearly loved physician, and Demas send you greetings.
23 Epaphras, my fellow prisoner in Christ Jesus, sends you greetings, and so do 24 Mark, Aristarchus, Demas, and Luke, my coworkers.
2 Tim 4:11 Only Luke is with me. Bring Mark with you, for he is useful to me in the ministry.
To the early church (and by early, I'm talking about records from the early second century), there was no doubt that Luke the physician, Paul's companion in ministry, wrote both the third Gospel and the book of Acts.
This also suggests that the famous "we passages" (where the author switches to the first person in 16:10-7, 20:5-15, 21:1-18, and 27:1-28:16) are times when Luke himself was present with Paul.
Important question: why wasn't Luke with Paul all the time? Simple answer: how many physicians do you think were converts to early Christianity, and how valuable do you think their skills would have been?
This answer helps us with the next big topic:
About Acts: The Date
If Luke, Paul's companion, wrote Acts, then we can expect a composition date somewhere within Paul's lifetime, right? Well, I sure think so.
What's included in Acts:
Paul's imprisonment in Rome -- ~AD 61-63 (Festus became governor in AD 60 according to official Roman records).
What's not included in Acts:
What happened to Paul after he got out of prison.
Nero's persecution of Christians starting AD 65.
The war between Jerusalem and Rome AD 66-70.
I admit that arguments from silence are not very conclusive. It could easily be argued that Luke didn't include some of those later events because he didn't need to; he simply wanted to demonstrate that the gospel had spread to Rome, and then his task was finished. HOWEVER -- Luke also ends his book on a hopeful note, which would be incomprehensible to the Christians living under Nero's persecution if he knew about it. That leads me (and many others) to believe that Luke wrote the book of Acts sometime between AD 62 and 64.
About Acts: The Purpose
Any historian worth his (or her) salt will tell you that it is impossible to write a complete and unbiased history book. That's because it's impossible to report "everything" about an event in history. Authors have limited space, and they cannot often ask questions like "why did you do that?" or "what was that closed-door discussion like?". The picking and choosing of what to include in a book means that every historian "shapes" his history book. What Luke chose to include, and how he organized his book, gives us a few clues as to his purpose.
Before I get into the weeds let me clear about one thing. First and foremost -- Luke wanted to write a careful and accurate history of Jesus and the early church. "This is what Jesus and the early leaders taught." "This is what God did." This gets into the question of "Who is Theophilus?" and "Why did Theophilus ask for this book?" Lots of theories out there (such as "theophilus" which means "lover of wisdom" was not an actual person). I think Theophilus was a wealthy "seeker" who was curious about Christianity but had many questions. He was willing to be Luke's patron to write this two-volume "history".
Writing a history takes a lot of time. There are lots of interviews to make. The materials for writing are expensive. And then there is all the travel. As we go through the book, I'll point out some obvious times Luke could have been doing his research while on mission with Paul, but the long and short is this undertaking would be expensive, and Theophilus was willing to help foot the bill.
Now let's get into some of the things Luke seems to emphasize:
The message of the church is the message of salvation in Jesus. Read the sermons and testimonies Luke included -- all very clearly declare the gospel of salvation. Luke wanted anyone who read this book to know how to be saved.
The church is for everyone -- Jews and Greeks and everyone else. That controversy is spelled out so carefully in this book; Paul's influence on this topic is pretty clear. Luke wanted everyone who read his book to believe the church was for them.
Christians are not Jews. There was a great deal of confusion about this in Rome. Romans thought Christianity was a sect of Judaism (like Pharisees), and they treated Christians with the same contempt as they did Jews.
Christians are not lawbreakers or insurgents. Repeatedly, Luke points out how Roman officials concluded that Christians were not rebels, nor was their teaching rebellious. This was an "apologetic purpose" -- defending Christianity to Rome.
Paul's Gentile mission is not at odds with Peter's Jewish mission. We will get into this later this quarter, but let me say now that Luke definitely gave equal importance to both Peter and Paul, and that's because there was tension in the early church.
Do those purposes make sense? If Theophilus (being wealthy) was an important Roman citizen, then he (or she) would want some assurances that he would really be welcomed and valued in his local church and that that he wasn't getting caught up in some kind of Jewish insurrection or infighting.
[Kinda like today, right? People today, when they come to a church, want to know that they will be welcomed and valued and not in some sort of weird cult, right?]
But let me camp out on that #5. At the top, I mentioned the importance of a church history book. And while there's certainly some nostalgia and some warnings, those books are super-useful to new people (particularly new pastors) coming into the church. Why are things the way they are? Who did what in the past? What hot-button issues have been worked through? That's also what Luke was accomplishing in Acts. Think about it this way -- who would be the vast majority of the new converts to the Christian church? Gentiles. People who had never been to Jerusalem. People who might not know anything about Judaism. People who might say, "Why should we care what somebody in Jerusalem says?" "Who is this Peter guy? This James guy?" Luke wanted to help everybody in the Christian movement understand where and how and why the church started. You might find it strange to know that we know more about the early church today than the people living in it! Why? Because we have four Gospels, the book of Acts, a bunch of letters from early church leaders, and 2,000 years of compiling what we know. The people living in, say, Ephesus had a visit from Paul, some stories helping them understand that Jesus was the only way to be saved, and a few basic doctrines about truth, right living, and what churches should do. They didn't know much (if anything) about Peter or John or Mary Magdalene or any of the others.
I don't know if we could ever understand what building a church would be like without having the book of Acts to help us.
I'm going to stop there. This has already taken too much space, and we will have a chance to talk about controversies related to the book of Acts as we go through this series.
A Summary of What You Need to Know
I covered a lot. Here are the highlights:
The book of Acts was written by Luke the physician, someone who served with Paul on parts of his missionary journeys. It was commissioned by a likely-wealthy Gentile seeker who wanted to know what this Jesus movement was really about. Luke used those resources to produce the carefully-researched duology of the Gospel of Luke and Acts, explaining who Jesus was, what He taught and did, where the church came from, and what the church is supposed to do. Luke emphasized a presentation of the facts of salvation, that salvation is available to all people regardless of ethnicity or social class, and that Christianity should be welcomed in Roman society as a force for good. All of that suggests a composition date of the early 60s before Nero unleashed his brutal persecution of Christians.
This Week's Big Idea: IMB's "The Great Pursuit"
When I see the phrase in this week's passage, "to the ends of the earth", my gut reaction is to ask, "How are we doing?" This seems like the right time to remind you guys about the International Mission Board's new initiative called "Project 3000".
Their website answers my basic question:
Over 3,000 people groups around the world have no missionary presence and likely no gospel access. No one is engaging them. Until now. The vision God gives us in Revelation 7:9 — a multitude from every nation, all tribes and peoples and languages — fuels our desire to take the gospel to the ends of the earth. But, we must be willing to go further than ever before — to the edges of lostness.
And here is their proposal:
WHAT WILL WE DO? We’ll send 300 explorers over 5 years to explore 3,072 unengaged people groups. This pioneering initiative, Project 3000, will create 100 new jobs each year over three years. Each of these missionaries will be exploring 10 people groups over a two year period. We’ll be journeying into the unknown to find out where they live, learning about their culture, discerning their literacy, developing ministry strategies and more.
[Btw: on their website, you'll find additional resources as well as a signup for updates. I absolutely encourage anyone to sign up for their updates.]
The IMB says that more than half of the 8 billion people on the planet have not heard the gospel. The non-denominational Joshua Project estimates that 42% of the earth's population does not even have access to the gospel. What are you going to do to help change that?
When we studied the end of Luke in 2021, I linked to a number of additional resources from the IMB and the Joshua Project. Some of the information is still a few years old, but if you want more about world missions, this post will help you:
Part 1: Jesus Has a Plan for His Church (Acts 1:4-8)
4 While he was with them, he commanded them not to leave Jerusalem, but to wait for the Father’s promise. “Which,” he said, “you have heard me speak about; 5 for John baptized with water, but you will be baptized with the Holy Spirit in a few days.” 6 So when they had come together, they asked him, “Lord, are you restoring the kingdom to Israel at this time?” 7 He said to them, “It is not for you to know times or periods that the Father has set by his own authority. 8 But you will receive power when the Holy Spirit has come on you, and you will be my witnesses in Jerusalem, in all Judea and Samaria, and to the ends of the earth.”
Really, to get into this lesson, I recommend that you go back to the end of Luke's Gospel:
24: 36 As they were saying these things, he himself stood in their midst. He said to them, “Peace to you!” 37 But they were startled and terrified and thought they were seeing a ghost. 38 “Why are you troubled?” he asked them. “And why do doubts arise in your hearts? 39 Look at my hands and my feet, that it is I myself! Touch me and see, because a ghost does not have flesh and bones as you can see I have.” 40 Having said this, he showed them his hands and feet. 41 But while they still were amazed and in disbelief because of their joy, he asked them, “Do you have anything here to eat?” 42 So they gave him a piece of a broiled fish, 43 and he took it and ate in their presence.
44 He told them, “These are my words that I spoke to you while I was still with you—that everything written about me in the Law of Moses, the Prophets, and the Psalms must be fulfilled.” 45 Then he opened their minds to understand the Scriptures. 46 He also said to them, “This is what is written: The Messiah will suffer and rise from the dead the third day, 47 and repentance for forgiveness of sins will be proclaimed in his name to all the nations, beginning at Jerusalem. 48 You are witnesses of these things. 49 And look, I am sending you what my Father promised. As for you, stay in the city until you are empowered from on high.”
50 Then he led them out to the vicinity of Bethany, and lifting up his hands he blessed them. 51 And while he was blessing them, he left them and was carried up into heaven. 52 After worshiping him, they returned to Jerusalem with great joy. 53 And they were continually in the temple praising God.
That leads directly into the first few verses of Acts:
1:1 I wrote the first narrative, Theophilus, about all that Jesus began to do and teach 2 until the day he was taken up, after he had given instructions through the Holy Spirit to the apostles he had chosen. 3 After he had suffered, he also presented himself alive to them by many convincing proofs, appearing to them over a period of forty days and speaking about the kingdom of God.
You can see that Luke carefully set up the book of Acts through his Gospel ending --
Jesus has helped them understand the truth of the Bible;
Jesus has given them the mission to take that truth to all nations;
Jesus has promised them "help" from the Father.
Jesus was with them for 40 days then commanded them to wait a few days more.
Let's just make sure everybody appreciates how brilliant a writer Luke is.
We will talk about Pentecost and being "baptized with the Holy Spirit" next week. You have plenty to cover without opening that huge topic quite yet! Try to hold your group off from going too far down that road this week. This week is about introducing the book of Acts and seeing how Luke has paved the way for the reader to understand how the new church will grow and spread.
I said this in the 2016 post -- we think of the book of Acts as explaining what the early church did and why. But first, Luke wants us to know what the early church was supposed to do.
A lot of studies get caught up in the "Father's promise" and "not for you to know" and "Jerusalem to ... ends of the earth". And that's fine and important! But first, let's make sure we understand ...
What are the key verbs in 1:8? Receive power and be witnesses. What do those two things help us understand about what Jesus was prioritizing?
"Receive power" ties directly to the "Father's promise", which gets into Pentecost and the baptism with the Holy Spirit. Again -- next week! The point for us right now? Jesus had a plan for His church, and He had a plan to help them accomplish it.
I recently read a story about a church planter who gave up and went into another line of work. He had all sorts of plans for how and where he was going to plant a church and what he was going to do there. But were they God's plans on God's timetable?
Jesus gave His followers a mission.
And then He told them to wait.
Why would Jesus tell them to wait? What was His purpose for doing so?
That ties into the other common rabbit trail in this passage -- "are You going to restore the kingdom now?" Why would the disciples ask that? Because they hoped to be going out as heralds, as conquerors themselves. Jesus had to cut that line of thinking off immediately. "Yes, I am going to reign as King of kings, but not here and not yet. You are going out as My heralds, but not as military conquerors, but rather as My martyrs."
Do you see how Jesus is immediately setting the tone for His church? "Just as I gave My life for the world, so will you give your lives for the world."
Jesus gave His life to bring salvation to sinners. Jesus' followers are to give their lives to bring the message of salvation to sinners. See the difference?
[Aside: the word for "witness" is the word for "martyr". Today, we solely associate martyrs with dying for the cause. You do not have to die to give your life, if that makes sense. Not everybody Jesus was talking to was killed for their faith in Christ, but many of them were.]
And then we have 1:8, the verse that (rightly) gets quoted at every mission fair and conference. You already know the progression Jesus gave them:
Here are two valuable insights you will hear repeated consistently:
This progression is not just geographic but ethnic and cultural.
This progression is not sequential but simultaneous.
I agree completely with those. Do they make sense to you?
I feel like I have covered way too much information so far in this post. Let me summarize the main points from this first part:
God will empower the church to this work.
The church's work is one of self-sacrifice, not conquering.
The church's mission is to all the earth.
The church is to be a witness to Jesus Christ our Lord.
Those things are true of your church today. If your church is not consistently about those priorities, then you are prioritizing the wrong things.
Aside: When Churches Get Distracted
Let's be honest -- churches get distracted. Churches focus on the wrong things. Much of the New Testament exists because churches almost immediately got caught up in the wrong priorities. So, what do you do when you think your church isn't focused on the right thing?
First thing is to look inward. How are you doing as a follower of Jesus Christ and witness for Him? Perhaps your church is having trouble because all of the members are individually distracted.
Second thing is to get more involved. Perhaps your church is doing things to accomplish the mission that you didn't know about. Or perhaps there are more obstacles your church is facing then you realized.
Third thing is to engage and support your church leaders. Are the leaders bogged down with aspects of ministry that prevent them from focusing on the church's witness? (More about this in Acts 6.) What can you do help them?
Fourth thing is to encourage your church leaders to focus on the mission. If you get through those first three steps and you still feel like the Holy Spirit is leading you to helping your church refocus on the mission, have a conversation with your pastor.
That might not be the dramatic answer you were hoping for, but I think it's a good answer. In my experience, most church leaders and church members truly want to follow Jesus and help their church to do the same. Life is tough. Following Jesus is tough. Being a church is tough. If it were easy, I daresay that history would have gone quite differently.
Part 2: There Will Be a Deadline for the Church (Acts 1:9-11)
9 After he had said this, he was taken up as they were watching, and a cloud took him out of their sight. 10 While he was going, they were gazing into heaven, and suddenly two men in white clothes stood by them. 11 They said, “Men of Galilee, why do you stand looking up into heaven? This same Jesus, who has been taken from you into heaven, will come in the same way that you have seen him going into heaven.”
This is one of my favorite passages in the Bible. The disciples had just watched Jesus float up into the sky and disappear into a cloud. They haven't even had a moment to pick up their jaws before two angels show up with a "Chop, chop!"
That's so great.
Of course, Luke includes this wonderful detail because God wants the church to know that there is a deadline for their work. God is not sending Jesus to conquer the world right now, but Jesus is coming back. And when He does, the work will be finished.
A lot of people look forward to retirement. They like the idea of taking a break from their work. But that's not the kind of work Jesus commissioned His church to do. Our business is the eternal destination of souls. When our work is finished (i.e., when we die or Jesus returns), there will be no more opportunity for souls to be saved.
Verse 11 is church-defining for two main reasons:
The disciples would probably have been disappointed to hear the Jesus was not establishing His eternal kingdom at that moment. This should overcome that. They are still serving the King of kings. The church is the servant of God Almighty.
The church stands on the edge of a new era. We proclaim a world that is to come, but that is not entirely yet. We live with the hope of a sure future with a world filled with people that we want to share that future with us.
That's a lot packed into a verse!
Aside: The Resurrection from the Dead
This post has already exceeded my regular length, so I'm going to punt. The physical resurrection from the dead and Jesus' physical return to earth are two key doctrines of Christianity. We've talked about them many times, so please take a look at --
There I try to establish some things we can agree on:
Christ's return is preceded by catastrophic conflict on earth.
Christ's return is announced by signs and trumpets.
Christ gathers Christians alive and dead (resurrected) to Himself.
Christ defeats all of His enemies.
When we studied the end of Luke, I also included quite a bit about the resurrection, what it means to have a "glorified body", and why this doctrine is so critical to Christianity.
Part 3: Preparations Are Made (Acts 1:23-26)
23 So they proposed two: Joseph, called Barsabbas, who was also known as Justus, and Matthias. 24 Then they prayed, “You, Lord, know everyone’s hearts; show which of these two you have chosen 25 to take the place in this apostolic ministry that Judas left to go where he belongs.” 26 Then they cast lots for them, and the lot fell to Matthias and he was added to the eleven apostles.
We did not cover this passage when we studied Acts in 2016. I think it's an important detail, and I'm glad Luke included it.
Jesus told the disciples to "wait" in Jerusalem. But they rightly noticed that He did not tell them to "sit and do nothing". Luke tells us that the first disciples waited together (in the famous upper room) and prayed. We also learn that Jesus' earthly family had joined in.
Luke tells us that the first disciples numbered about 120. That probably would have been a tight fit in the upper room, so this event may have taken place somewhere else.
Peter, who has realized he needs to be a leader, tells the group that Judas' betrayal was necessary, and they need to move on. This was very important because otherwise suspicion could have completely destroyed them.
[Aside: how do we reconcile what Luke says about Judas with what Matthew says (27:5)? Matthew says that Judas hanged himself and the Sanhedrin bought the field. Here's how I have understood that: (1) Judas bought the field and hanged himself on it. (2) Nobody went anywhere near him, knowing what he had done to Jesus. (3) His body rotted until the rope or the tree broke and he spilled onto the field. (4) Someone from the Sanhedrin eventually bought the field for cheap. Because of course they did.]
Peter gives some criteria for whoever would "replace" Judas: they had to have been a witness of Jesus' ministry from beginning to end. Note that this means there were more people with Jesus than just "The Twelve"! I think that's a big deal. The Jesus movement isn't just about officials with titles; it's about everybody, including people whose names didn't make the Bible.
I say that, but these two men did make the Bible, after all. Joseph/Justus and Matthias. How did they choose between them? They prayed, and they threw dice.
Really. 😎 I love the book of Acts.
They had determined that both Joseph and Matthias would make equally wonderful apostles, and they did not know how to choose between them. So, they asked God to divinely guide the dice roll. (*giggle*)
Note, we don't actually know for certain what "casting lots" meant. And Luke isn't telling us to make decisions that way today! Your leader guide mentions a "draw straws" activity to set the mood. I like that, but be absolutely clear that any outcome would have been acceptable by the criteria they set. The disciples were not putting God to the test by including some randos in the pot.
Aside: Why Was "Twelve" So Important?
We have the benefit of the rest of the New Testament, so we understand the symbolism of "12". Would the disciples have caught that? Of course! They could count. They saw that Jesus had deliberately chosen 12 men to call "Disciples", and they knew their Jewish history
Closing: Putting It All Together
In the book of Acts, we're going to learn not just what happened in the early church, but also why. This first lesson has been about establishing the core principles:
The church should only act in God's power and wisdom;
The church should act with great urgency;
The church will be a self-sacrificing witness of Jesus to the nations;
The church should trust God's leadership and direction.
Final Aside: "The Church"
You're going to catch me writing "the church" a lot when we study Acts. Notice that I'm not writing "The Church". In the New Testament, they most often use the word "church" to describe either a local body of believers or the collective group of all living Christians. Therefore, when I say "the church", I'm talking about "local churches" and also "every church". The things that Luke reports apply to your church, my church, and every other Christian church. Therefore, I say "the church" to acknowledge that we're all supposed to be in this together. Things lie "The Methodist Church" and "The Catholic Church" are all much later developments. I simply want to acknowledge that one day, every Christian will be gathered around the throne of God as "the church". We won't have labels.