John Calvin on Acts 8:4

4. And they were scattered abroad. Luke declareth in this place also, that it came to pass by the wonderful providence of God, that the scattering abroad of the faithful should bring many unto the unity of faith; thus doth the Lord use to bring light out of darkness, and life out of death. For the voice of the gospel, which was heard heretofore in one place only, doth now sound everywhere; in the mean season, we are taught by this example that we must not yield unto persecutions, but rather be encouraged unto valiantness; for, when the faithful flee from Jerusalem, they are not afterward discouraged either with exile or with their present miseries, or with any fear, that they degenerate into slothfulness; “Ad ignaviam vel tarditatem,” unto sloth or cowardice. but they are as ready to preach Christ even in the midst of their calamity as if they had never suffered any trouble. Moreover, Luke seemeth to note that they led a wandering life in that they changed their lodgings often. Therefore, if we desire to be counted their brethren, let us prick forward ourselves so diligently, that no fear or bitterness of cross discourage us, but that we go forward in showing forth the profession of faith; and that we never be weary of furthering the doctrine of Christ; for it is an absurd thing that exile and flight, which are the first exercises of martyrdom, should make us dumb and fainthearted.

Acts 8:5-13

5. And when Philip came into the city of Samaria, he preached Christ to them. 6. And the multitude gave ear to those things which Philip spake, hearing with one consent, and seeing the signs which he showed. 7. For whereas many were possessed with unclean spirits, they came out, crying with a loud voice; and many that had the palsy, and which were lame, were healed; 8. So that there was great joy in that city. 9. And a man, named Simon, had been before in the city, exercising the art magic, and bewitching the people of Samaria, saying that he was some great man: 10. To whom they all gave heed, both small and great, saying, This man is the great power of God. 11. And they had given heed unto him, because they had been bewitched long time with his witchcraft. 12. But as soon as they believed Philip preaching concerning the kingdom of God, and in the name of Jesus Christ, they were baptized, both men and women. 13. And Simon himself believed, and being baptized, did cleave to Philip; and when he saw the signs and great powers which were done, he wondered.