Yeremia 50:3

50:3 For a nation from the north ¹  will attack Babylon.

It will lay her land waste.

People and animals will flee out of it.

No one will inhabit it.’

Yeremia 50:41

50:41 “Look! An army is about to come from the north.

A mighty nation and many kings ²  are stirring into action

in faraway parts of the earth.

[50:3]  ¹ sn A nation from the north refers to Medo-Persia which at the time of the conquest of Babylon in 539 b.c. had conquered all the nations to the north, the northwest, and the northeast of Babylon forming a vast empire to the north and east of Babylon. Contingents of these many nations were included in her army and reference is made to them in 50:9 and 51:27-28. There is also some irony involved here because the “enemy from the north” referred to so often in Jeremiah (cf. 1:14; 4:6; 6:1) has been identified with Babylon (cf. 25:9). Here in a kind of talionic justice Judah’s nemesis from the north will be attacked and devastated by an enemy from the north.

[50:41]  ² sn A mighty nation and many kings is an allusion to the Medo-Persian empire and the vassal kings who provided forces for the Medo-Persian armies.