(12) But when they believed Philip . . . .—The word for preaching is, as in Acts 8:4, “preaching the glad tidings of the kingdom of God.” The sequel shows that this included baptism as the outward condition of admission to the kingdom. We may infer from the other narrative of Philip’s mission-work (Acts 8:31-35) that it also included an outline-history of the passion and death and resurrection of the Prophet whom they had seen among them as fulfilling the great Messianic prophecies.

They were baptized, both men and women.—The tense points, not to one great act, but to the continual succession of converts who were thus admitted. We think of the woman of Samaria, of John 4:7, and wonder whether she was one of them.

Acts 8:12-13. But when they believed Philip, &c. When they became spectators of Philip’s miracles, and were convinced that they were real, and those of Simon a mere sham; or, when they believed the doctrine that Philip preached, concerning the kingdom of God, they then saw and felt the real power of God, and submitted thereto; and were baptized, both men and women — Thus making an open profession of their faith in the gospel. By the influence of divine grace, working with the word, they that had been led captive by Satan, were brought into obedience to Christ. Then Simon himself believed — The truth of the doctrine taught by this messenger of God, though his heart was not truly changed by its power: and when he was baptized — On a profession of that faith; he continued with Philip — Courting a further acquaintance with him; and wondered, beholding the miracles, &c. — Greek, was astonished, or filled with amazement, as the Samaritans had formerly been, at the sight of his magical performances. “It is with peculiar elegance and propriety, that the same word which had been used to express the manner in which the Samaritans were affected with Simon’s enchantments, is here used to describe the impression which Philip’s miracles made on him.” Thus Doddridge; who adds, “We see in this, as in a thousand nearer instances, that there may be a speculative faith in the gospel where there is no true piety; and if such persons, on the profession of that faith, where nothing appears contrary to it, be admitted to those ordinances by which Christians are distinguished from the rest of mankind, it is an evil in the present state of things unavoidable, and the conduct of Christian ministers and societies, in admitting such, will be less displeasing to God than a rigorous severity.”

8:5-13 As far as the gospel prevails, evil spirits are dislodged, particularly unclean spirits. All inclinations to the lusts of the flesh which war against the soul are such. Distempers are here named, the most difficult to be cured by the course of nature, and most expressive of the disease of sin. Pride, ambition, and desire after grandeur have always caused abundance of mischief, both to the world and to the church. The people said of Simon, This man is the great power of God. See how ignorant and thoughtless people mistake. But how strong is the power of Divine grace, by which they were brought to Christ, who is Truth itself! The people not only gave heed to what Philip said, but were fully convinced that it was of God, and not of men, and gave up themselves to be directed thereby. Even bad men, and those whose hearts still go after covetousness, may come before God as his people come, and for a time continue with them. And many wonder at the proofs of Divine truths, who never experience their power. The gospel preached may have a common operation upon a soul, where it never produced inward holiness. All are not savingly converted who profess to believe the gospel.The great power of God - Probably this means only that they believed that he was "invested with" the power of God, not that they supposed he was really the Great God. 12. were baptized, both men and women—the detection of Simon's frauds helping to extend and deepen the effects of Philip's preaching. When they believed; before they were baptized, being adult and strangers from the covenant, they must first evidence their right unto it, and profess their faith in Christ, and testify their conversation.

Concerning the kingdom of God; the kingdom of grace, and the kingdom of his glory, which is one and the same, being begun here, but consummated in heaven hereafter.

Both men and women; women under the gospel are as capable of this seal of the covenant as men.

But when they believed Philip,.... Though they had been carried away so long with this deceiver, and had been so much attached unto him, and held in admiration of him; yet when Philip came and preached Christ unto them, such was the power that attended his ministry, and such the efficacy of divine grace that was exerted, that they not only gave heed unto him, but believed what he said:

preaching the things concerning the kingdom of God; concerning the kingdom of the Messiah, the Gospel dispensation, the doctrines and ordinances of the Gospel; and concerning the kingdom of grace, which is spiritual and internal, and which lies not in external things, as meat and drink, but in righteousness, peace, and joy; and concerning the kingdom of glory, the meetness for it, which lies in regenerating grace, and the right unto it, which is the righteousness of Christ:

and the name of Jesus Christ; concerning the person of Christ, as the Son of God: and the offices of Christ, as prophet, priest, and King; and the virtue of his blood, righteousness, and sacrifice, for pardon, justification, and atonement: the Vulgate Latin, Syriac, and Ethiopic versions read this clause, "in the name of Jesus Christ": and connect it with the following words,

they were baptized, both men and women: that is, when, they heard Philip preach the Gospel, and believed in Christ, the sum and substance of it, and made a profession of faith, they were of each sex, both men and women, baptized by immersion, in the name of Jesus Christ.

But when they believed Philip preaching the things concerning the kingdom of God, and the name of Jesus Christ, they were baptized, both men and women.