to blow away: to sweep a weightless thing off on a rush of wind so that it scatters and is nowhere to be found
This is a wind word. Almost every time it appears, something with no weight to it is caught by moving air and taken off: chaff on a threshing floor, dry stubble ahead of an advancing army, a single leaf on the ground, a column of smoke, a puff of breath. The picture is not of being pushed slowly along. It is of being gone in an instant, with nothing left to point at.
Because of that, the biblical writers reach for it whenever they want to say that something looks solid but has no substance:
- money piled up by lying is only a breath already blowing off
- the wicked have no more staying power than chaff on a windy threshing floor
- Job asks whether God would trouble himself to terrify one windblown leaf
- the rustle of a single leaf is enough to send terrified exiles running
- crops along the Nile dry out and blow away until there is nothing there
The second use of the word follows straight from the first. If God can blow smoke off the air, he can do the same to those who set themselves against him, and two passages say exactly that. Psalm 68 sets both halves side by side: as smoke is blown away, so blow them away. There the word turns active, with God as the one doing it, and his enemies take the place of the smoke.
It helps to see what the word does not mean. It is not the ordinary term for breaking a crowd apart in every direction (פּוּץ), and it is not the term for shoving someone out of a place (גָּרַשׁ). It is the lighter, quicker picture: too weightless to stay, so the wind takes it.