Peter’s message presents the gospel, and God opens the eyes of 3000 people to repent of their sin and turn to Jesus. Now, those 3000 are looking to live out this new identity in Christ as this gospel begins to bear fruit in their lives.
The Spirit came, and a crowd assembled when they heard the noise. But, upon hearing these Galileans speak other languages fluently, they assumed these hillbillies had been drinking before prayer. Peter, now filled with the Spirit, stands up and corrects them, giving the first explicitly Christian sermon ever given.
As the 120 disciples of Jesus are gathered in the Upper Room, they are together for morning prayer, praying for the Holy Spirit to come, and suddenly, without warning, the Spirit came in power!
Jesus had promised his Holy Spirit will come on the disciples, then he ascended, and now the disciples head back to Jerusalem to wait. What do you tend to do when you have to wait? These 120 disciples waited by praying and making a major decision about who replaces Judas.
Luke starts out his second narrative like a new driver adjusting the rearview mirror, remembering where we've come from in terms of Jesus' life, death, resurrection, and ascension. He reminds us of the promise of the Father, and gets us ready for the mission: Be My Witnesses. And then he ascends.