John Calvin Commentary Acts 17:23

"For as I passed along, and observed the objects of your worship, I found also an altar with this inscription, TO AN UNKNOWN GOD. What therefore ye worship in ignorance, this I set forth unto you." — Acts 17:23 (ASV)

To the unknown God. I can well grant that this altar was dedicated to all foreign gods; yet I cannot agree with what Jerome says, that Paul, by a certain holy craftiness, attributed to one God what was written of many. For since the inscription was common knowledge, there was no place for craftiness; why then did he change the plural number?

Surely, it was not that he might deceive the Athenians, but because the matter so required, he said that he brought teaching concerning an unknown god. And after he has shown that they are deceived—because they did not know what god they ought to worship and had no certain deity among a great multitude of gods—he now subtly introduces himself and gains favor for his teaching.

For it was an unjust thing to reject what was spoken concerning a new god to whom they had already committed themselves; and it was far better first to know him than rashly to worship him whom they did not know. Thus Paul returns again to that principle: God cannot be worshiped rightly unless He is first made known.

But here a question may be raised: how can Paul say that God was worshiped at Athens, when God Himself refuses all worship that is not in accordance with what His law prescribes? Indeed, He declares that everything people invent apart from His Word is idolatry.

If God allows no worship except that which is consistent with His Word, how does Paul offer this praise to people who were so immoderately zealous in worshiping God?

For Christ, in condemning the Samaritans, bases His argument on this one principle: they worship God without knowledge (John 4:22), even though they boasted that they worshiped the God of Abraham.

What, then, shall we say of the Athenians, who, having buried and completely extinguished the remembrance of the true God, had put in His place Jupiter, Mercury, Pallas, and all that filthy rabble?

I answer that Paul does not, in this instance, commend what the Athenians had done. Instead, he draws from their religious sentiment—corrupt though it was—ample material for his teaching.