John Calvin Commentary Isaiah 13:17

"Behold, I will stir up the Medes against them, who shall not regard silver, and as for gold, they shall not delight in it." — Isaiah 13:17 (ASV)

Behold I raise up against them the Medes. The Prophet, having predicted the destruction of the Babylonians, also describes the authors—or rather, states that God will be the author. At the same time, he explains how, and through whom, it will be accomplished, for he says that He will raise up the Medes. He certainly could not have conjectured this by human reason, for there was no jealousy or quarreling between the Babylonians and the Medes. And if there had been any such, what power did the Medes at that time possess that they could do the Babylonians any harm?

Therefore, since no preparations had been made for the Medes to wage war against them, it is very certain that this was spoken by divine inspiration, especially since he foretold these events more than a hundred years before they took place.

Who shall not think of silver, nor desire gold. When he says that they shall not be covetous of silver and gold, he does not mean that the Medes were not guilty of plundering and covetousness, as if they were so generous that they despised gold and silver. On the contrary, he means that the battle will be cruel and bloody, and that they will aim at nothing but a general slaughter. For example, the Spaniards of the author's present day, making it their chief object in war to plunder, more readily spare human lives and are not so bloodthirsty as the Germans or the English, who think of nothing but slaying the enemy.

We should not think it strange that the Lord, though He is not cruel, nevertheless uses such cruel agents, for He acts righteously even through the agency of wicked men and is not stained by their wickedness. Therefore, it would be improper to judge God’s work based on His executioners, for they are prompted by ambition, covetousness, or cruelty. Instead, we should consider God’s righteous punishment, which the Babylonians deserved because of their transgressions.