John Calvin's Bible Commentary
Jeremiah 51:40
This is a comparison different from the former, when the Prophet said that they would be like lions, but as to roaring only. But he now shows how easy would that ruin be when it should please God to destroy the Babylonians. Then as to their cry, they were like lions; but as to the facility of their destruction, they were like lambs led to the slaughter. God does not mean here that they would be endued with so much gentleness as to give themselves up to a voluntary death; but he means, that however strong the Babylonians might have previously been, and however they might have threatened all other nations, they would then be women in courage, and be led to the slaughter as though they were lambs or rams.
This is a comparison which occurs often in the prophets, for sacrifices were then daily made; and then the prophets considered the destruction of the ungodly as a kind of sacrifice; for as sacrifices were offered under the Law as evidences of piety and worship, so when God appears as a judge and takes vengeance on the reprobate, it is the same as though he erected an altar, and thus exhibited an evidence of the worship that is due to him; for his glory and worship is honored, yea, and celebrated by such sacrifices. Then the destruction of all the ungodly, as we have said, may be justly compared to sacrifices; for in such instances the glory of God shines forth, and this is what especially belongs to his worship. It at length follows, —