John Calvin Commentary Acts 8:11

"And they gave heed to him, because that of long time he had amazed them with his sorceries." — Acts 8:11 (ASV)

When he says that they were astonished, from the least to the greatest. For since all people, whatever their status, were deluded, what entry could the gospel have, especially since it was no insignificant seduction, as all their senses were stupefied? And besides our recognizing through this how mighty the truth is, an example of constancy in Philip is also set before us, who, though he saw no way, yet undertook the Lord’s work with valiant courage, waiting for the success that God would give.

This is what we must do: we must valiantly attempt whatever the Lord commands, even when our efforts seem to be futile. Furthermore, since Satan did bewitch the Samaritans, let us understand that this is the common punishment for unbelief. Indeed, not all people are bewitched with the deceptions of enchanters, nor are there Simons everywhere who can so seduce and deceive; but my meaning is that it is no wonder if Satan mocks people in various ways in the dark, for all those who are not governed by the Spirit of God are subject to all errors.

Furthermore, when Luke says that they were all seduced collectively, we are taught that neither intelligence, nor all the reason and wisdom we possess, are sufficient to avoid the craftiness of Satan. And surely we see in what foolish and absurd errors those were entangled who were considered in the world to be wiser than others.

The great power of God. Therefore, Satan abused the name of God to deceive, which is the most pernicious kind of deceiving, and this is far from being any excuse. It has been said before that Simon took to himself the name of the principal power of God, so that he might suppress and surpass whatever was elsewhere divine, just as the sun darkens all the stars with its light.

This was a wicked and ungodly profanation of the name of God. But we read of nothing done here that is not still done daily, for people are more inclined to nothing else than to attribute to Satan what is proper to God. They pretend to be religious, but what did this pretense do to help the Samaritans?

Therefore, it goes well with us when God sets forth to us his power in Christ, and thereby declares that we must not seek it anywhere else, and reveals the deceptions and trickery of Satan, which we must avoid, so that he may keep us continually in himself.