But you are to be given power when the Holy Spirit has come to you. You will be witnesses to me, not only in Jerusalem, not only throughout Judea, not only in Samaria, but to the ends of the earth. Acts 1:8, Phillips.
When we think of world mission we too often have a mental image of going far away to some foreign land where the "heathen" have never heard about Jesus. Christ, Himself, set forward just the opposite program. His command is for us to start with the "heathen" in our own town.
For the earliest disciples that meant Jerusalem. Jesus had sown gospel seed in the Jewish metropolis for years. It was there that He "had been condemned and crucified. In Jerusalem were many who secretly believed Jesus of Nazareth to be the Messiah, and many who had been deceived by priests and rulers. To these the gospel must be proclaimed? (The Acts of the Apostles, p. 31).
What we find in the book of Acts is the filling out of the mission program or schedule set forth in Acts 1:8. Obeying Jesus' advice, His followers first preached the gospel in Jerusalem. And the fruit came fast because of the many waiting hearts who had already known about Jesus but had not yet decided to dedicate their lives to Him. The harvest was now ripe and about 3,000 Jewish believers would be baptized on the day of Pentecost (Acts 2:41), with more joining the church with each passing day (verse 47). Even "a great many of the priests" became "obedient to the faith" (Acts 6:7, RSV).
While the first post-Pentecostal step in Christian mission took place in Jerusalem (Acts 2-6), the martyrdom of Stephen (Acts 7) led to the believers being "scattered throughout the region of Judea and Samaria" (Acts 8:1, NKJV). And with that event the action of Christian mission broadened, like the rings in water caused by a falling stone. Acts 8 highlights the ministry of Philip in Samaria. Then Acts 10 features Peter reluctantly bringing the message of Christ to a Gentile. And with the conversion of Cornelius the non-Jew the way opened for the gospel to go the rest of the world, a process that Acts sets forth in the work of the apostle Paul from Acts 13 to 28.
Paul's work, of course, is just one arm of the apostolic mission to take the gospel to the ends of the earth. As we noted earlier, Thomas carried it to Persia and probably India. Others proclaimed Christ in Africa and other places. The ever-widening circle of Christian outreach will continue until the "whole world" has heard the message of the risen Christ. "Then the end will come" (Matt. 24:14, RSV).