The subjects of this verse are evidently Peter and John. The fact that while they were returning to Jerusalem the apostles preached the gospel in other Samaritan towns shows that they fully accepted the Samaritans as fellow believers. Furthermore they welcomed them into the church. Quite a change had taken place in John's heart in particular, and in Peter's, since these disciples had visited Samaria with Jesus (cf. Luke 9:52-54). John had wanted to call down fire from heaven on a Samaritan village.
This mission into Samaria constituted a further gospel advance to the Gentiles. The Jews regarded the Samaritans as half Jew and half Gentile. In view of Peter's later reluctance to go to the Gentiles (ch. 10) this incident was clearly part of God's plan to broaden his vision. It prepared him to accept Gentiles into the church equally with Jews.
