Charles Ellicott Commentary Jeremiah 4:7

"A lion is gone up from his thicket, and a destroyer of nations; he is on his way, he is gone forth from his place, to make thy land desolate, that thy cities be laid waste, without inhabitant." — Jeremiah 4:7 (ASV)

The lion has come up ... —The “lion” is, of course, the Chaldean invader, the destroyer not only of men, but of nations. So in Daniel 7:4, the lion is the symbol of the Assyrian monarchy. The winged lions seen in the palaces of Mosul and Nimroud gave a special character to what was, in any case, a natural metaphor. The word “Gentiles” corresponds to the meaning, but there is no special reason why it should be used here, rather than nations.

Is on his way. —Literally, has broken up his encampment, i.e., has started on his march.

Without an inhabitant. —The language, like that of Isaiah (Isaiah 6:11), was probably in some measure hyperbolical, but the depopulation caused by the Chaldean invasion (as seen in Jeremiah 39:9) must have been extreme.