Charles Ellicott Commentary Jeremiah 46:22

"The sound thereof shall go like the serpent; for they shall march with an army, and come against her with axes, as hewers of wood." — Jeremiah 46:22 (ASV)

The voice thereof shall go like a serpent.— Better, her voice—that is, the voice of Egypt. In early prophecies, Egypt had been compared to a “dragon” or “serpent” (Isaiah 27:1; Isaiah 51:9; Psalms 74:13). Here the serpent is represented as hissing in its rage and terror in the forest against which the enemies are advancing. The sign then gives way to the thing signified. The latter clause of the verse brings before us the hosts of the Chaldean allies—barbarous tribes like the Scythians, Massagetae, and Sacae, armed with axes instead of swords or spears (Herodotus 1.275; 4.5).

They come, but it is to cut down the trees of the forest—that is, the symbols of the power of Egypt—and there is no power to resist them (Isaiah 10:33). The forest is so dense that the trees cannot be counted, but the fellers of the trees are as numerous, and the forest is destined for destruction at the hands of “the people of the north.”