Jamieson, Fausset and Brown on Habakkuk 1:9

9. all for violence--The sole object of all is not to establish just rights, but to get all they can by violence.

their faces shall sup up as the east wind--that is, they shall, as it were, swallow up all before them; so the horse in Job 39:24 is said to "swallow the ground with fierceness and rage." Maurer takes it from an Arabic root, "the desire of their faces," that is, the eager desire expressed by their faces. Henderson, with Symmachus and Syriac, translates, "the aspect."

as the east wind--the simoon, which spreads devastation wherever it passes (Is 27:8). Gesenius translates, "(is) forwards." The rendering proposed, eastward, as if it referred to the Chaldeans' return home eastward from Judea, laden with spoils, is improbable. Their "gathering the sand" accords with the simoon being meant, as it carries with it whirlwinds of sand collected in the desert.