Dr. Luke writes a careful account of the birth of the church. It is a new group of people called out of their homes, into regular gatherings, for the specific purpose of following Jesus their Redeemer. Jesus had come back from the dead. Jesus spent time with His followers proving that He was alive, teaching about the Kingdom of God, and instructing them to wait for the Holy Spirit and the enabling power of the living God. Jesus returned to Father God and they went into Jerusalem to wait on the Holy Spirit. 120 believers gathered into that place. Peter led an effort to install a new 12th apostle after the suicide of Judas. The followers of Jesus obeyed His instructions.