Job 15:2

2. a wise man—which Job claims to be.

vain knowledge—Hebrew, "windy knowledge"; literally, "of wind" (Job 8:2). In Ec 1:14, Hebrew, "to catch wind," expresses to strive for what is vain.

east wind—stronger than the previous "wind," for in that region the east wind is the most destructive of winds (Isa 27:8). Thus here,—empty violence.

belly—the inward parts, the breast (Pr 18:8).