C. F. Keil and Franz Delitzsch on Jeremiah 46:8-9

Jer 46:8-9 brings the answer to the question of astonishment: "Egypt approaches, its hosts cover the land like the waves of the Nile, to destroy cities and men." On the form  אבידה (with א contracted from אא), cf. Ewald, §192, d; Gesenius, §68, Rem. 1. עיר is used in an indefinite general sense, "cities," as in Jer 8:16. - In Jer 46:9, the imperat. stands as in Jer 46:3.: "Let the formidable army approach, - cavalry, chariots, and infantry, with all their splendidly equipped auxiliaries, - nevertheless it shall perish." עלוּ הסּוּסים does not here mean "Mount the steeds," which is against the parallelism, but "Get up (i.e., prance), ye horses;" this meaning is guaranteed by the Hiphil מעלה, as used in Nah 3:3. התהללוּ הרכב is an imitation of Nah 2:5. As auxiliaries, and very brave ones too (גבּורים), are mentioned "Cush," i.e., the Ethiopians; "Phut," the Libyans; and "Ludim," i.e., Hamitic, African Lydians, as in Eze 30:5. On the double construct in תּפשׂי דר, "holding, bending bows," cf. Ew. §280, c.