Jeremiah 50:8

In this chapter, and that which follows, we have the judgment of Babylon, which is put last of Jeremiah's prophecies against the Gentiles because it was last accomplished; and when the cup of God's fury went round (Jer 25:17) the king of Sheshach, Babylon, drank last. Babylon was employed as the rod in God's hand for the chastising of all the other nations, and now at length that rod shall be thrown into the fire. The destruction of Babylon by Cyrus was foretold, long before it came to its height, by Isaiah, and now again, when it has come to its height, by Jeremiah; for, though at this time he saw that kingdom flourishing "like a green bay-tree," yet at the same time he foresaw it withered and cut down. And as Isaiah's prophecies of the destruction of Babylon and the deliverance of Israel out of it seem designed to typify the evangelical triumphs of all believers over the powers of darkness, and the great salvation wrought out by our Lord Jesus Christ, so Jeremiah's prophecies of the same events seem designed to point at the apocalyptic triumphs of the gospel church in the latter days over the New Testament Babylon, many passages in the Revelation being borrowed hence. The kingdom of Babylon being much larger and stronger than any of the kingdoms here prophesied against, its fall was the more considerable in itself; and, it having been more oppressive to the people of God than any of the other, the prophet is very copious upon this subject, for the comfort of the captives; and what was foretold in general often before (Jer 25:12 and Jer 27:7) is here more particularly described, and with a great deal of prophetic heat as well as light. The terrible judgments God had in store for Babylon, and the glorious blessings he had in store for his people that were captives there…

50:8-9 The Lord urged the Israelites to leave when he ordered an army of great nations (Persia and its allies) to attack Babylon in 539 BC.