We read yesterday about how Peter preached about Jesus to the crowd that had gathered after hearing the disciples speaking in other languages. Peter's message about how Jesus was crucified and raised from the dead touched the crowd and led them to repentance. Peter invites them into discipleship as well and from there the church grows. Notice what Luke thinks is important about the church: rejoicing, fellowship, prayer, taking care of those in need and eating together. Not a bad starting point.