John Calvin Commentary Isaiah 19:17

"And the land of Judah shall become a terror unto Egypt; every one to whom mention is made thereof shall be afraid, because of the purpose of Jehovah of hosts, which he purposeth against it." — Isaiah 19:17 (ASV)

And the land of Judah shall be a terror to the Egyptians. Some explain it simply to mean that the land of Judah will be an astonishment to the Egyptians as well as to other nations, and compare this passage with the saying we have previously observed, You shall be an astonishment.

But I think that the meaning of the Prophet here is different, for he intended to point out the reason why the Lord would make such a display against the Egyptians. It was because they had brought destruction on the Jews, for they had turned them away from the confidence they should have placed in God, much as princes frequently solicit their neighbors and offer them aid, so that they may afterwards use them for their own advantage.

Now the Lord had forbidden them (Deuteronomy 17:16) to resort to the Egyptians for the purpose of asking assistance from them. But those wretched people, instead of obeying God, listened to the solicitation of unbelievers who made offers to them, and for this reason they were justly punished.

But the Egyptians also, who had given rise to their unbelief and distrust, did not go unpunished. They were so sharply chastised that whenever they remembered the Jews, they were overwhelmed with terror. Therefore, we should draw a profitable doctrine from this: those who have turned the Church aside from obeying and trusting in God, and who, by fear, counsel, or any enticements, have caused offense, will be severely punished.

The meaning of the Prophet’s words is like saying that the sight of a woman will make him who seduced her blush, when the disgrace of the uncleanness will have been exposed, and when God will come forth as the avenger of conjugal fidelity.