I will bring them down like lambs to the slaughter, like rams with male goats.
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.
Babylon was once a golden cup in the Lord's hand, filled with His favor, but also His battle-axe to break nations. Those that carry all before them a great while will yet meet their match; even Babylon's day will come, and it too shall fall.
AI summary
Commenting on Jeremiah 51:1-58
The sea is come up upon Babylon,.... A vast army, comparable to the great sea for the multitude thereof, even the army of the Medes and Persians under Cyrus; so the Targum, "a king with his armies, which are numerous like the waters of the sea, is come up against Babylon:'' she is covered with the multitude of the waves thereof; being surrounded, besieged, surprised...