Matthew Henry Commentary Acts 8:5-13

"And Philip went down to the city of Samaria, and proclaimed unto them the Christ. And the multitudes gave heed with one accord unto the things that were spoken by Philip, when they heard, and saw the signs which he did. For [from] many of those that had unclean spirits, they came out, crying with a loud voice: and many that were palsied, and that were lame, were healed. And there was much joy in that city. But there was a certain man, Simon by name, who beforetime in the city used sorcery, and amazed the people of Samaria, giving out that himself was some great one: to whom they all gave heed, from the least to the greatest, saying, This man is that power of God which is called Great. And they gave heed to him, because that of long time he had amazed them with his sorceries. But when they believed Philip preaching good tidings concerning the kingdom of God and the name of Jesus Christ, they were baptized, both men and women. And Simon also himself believed: and being baptized, he continued with Philip; and beholding signs and great miracles wrought, he was amazed." — Acts 8:5-13 (ASV)

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 of this kind. Spiritual ailments are mentioned here—those most difficult to cure by natural means and most expressive of the disease of sin. Pride, ambition, and the desire for grandeur have always caused a great deal of harm, 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 err. But how strong is the power of Divine grace, by which they were brought to Christ, who is Truth itself! The people not only paid attention to what Philip said but were fully convinced that it was from God, and not from men, and they surrendered themselves to be guided by it.

Even bad men, and those whose hearts are still set on covetousness, may come before God as His people do, and for a time continue with them. And many marvel at the proofs of divine truths, yet never experience their power. The preached gospel may have a common effect on a soul where it never produced inward holiness.

All are not savingly converted who profess to believe the gospel.