Jeremiah 51:49 - Ellicott's Commentary On The Whole Bible

As Babylon hath caused... — The interpolated words and the marginal reading indicate that the construction is obscure, but the Authorised version probably comes close to the meaning of the original. The punishment that falls on Babylon comes on account of her slaughter of the Israelites, but in that punishment other nations from all parts of the earth who are mingled with her people should be involved. Perhaps, however. we should read the slain of all the land, as giving more emphatically the law of retribution. The rendering of the margin, “Both Babylon is to fall, O ye slain of Israel, and with Babylon...” is adopted by some recent commentators, but gives a less satisfactory meaning.