From Acts of the Apostles, by William S. Kurz, SJ, commenting on Acts 8:5-8, 14-17
Luke shows that God continues to work his saving plan even through apparent setbacks. Here the persecution that forced disciples out of Jerusalem, which can certainly be regarded as a defeat for them on the human level, is directly used by God to spread his word of salvation. The very disciples who had been scattered went about preaching the word.
The followers of Jesus evidently regarded evangelization as a natural response to new circumstances, unexpected though they were. Philip, the second Hellenist named after Stephen in the list of those designated as leaders by the apostles (Acts 6:5), is the first missionary mentioned. He took the word to Samaria, where he proclaimed the Messiah to them.
Samaria was part of the area belonging to the northern kingdom of Israel, which split off from Judah after Solomon’s reign (1 Kings 12). Thee ten tribes of the northern kingdom were exiled into Assyria in 722 BC, and their land was repopulated with non-Israelites. By New Testament times, Jews regarded Samaritans as mixed-blood heretics who refused to worship in the temple at Jerusalem (see John 4:20). Philip’s mission is the first reported mission beyond Jerusalem, fulfilling what Jesus had prophesied in Acts 1:8.
Verse 6 repeats one of Luke’s favorite expressions to highlight the unity among those who heard the word preached by Philip: with one accord. The signs that Philip was doing moved the Samaritan crowds to pay attention to his preaching. Luke mentions especially Philip’s exorcisms and physical healings: unclean spirits cried out in a loud voice when they came out of many possessed people; there were also healings of many paralyzed and crippled people. All these wondrous signs worked by Philip resulted in great joy in that city.