chaff: the light husks and broken bits beaten off grain at threshing, so weightless that the wind carries them away
Grain was threshed on a flat, open floor and then tossed up into the evening breeze with a fork. The heavy kernels dropped back down and were swept into a pile. The light husks and shreds went off with the wind. Those husks are what this word names. Nobody gathered them, nobody went looking for them, and by morning they were simply gone.
The striking thing is that the Bible never once uses the word for an actual heap of husks. All eight appearances are comparisons, and in every one the thing being compared is on its way out:
- the wicked, who have no roots and cannot stand when God sifts (Psalm 1:4)
- enemies chased by the angel of the LORD until they scatter (Psalm 35:5)
- roaring nations that God rebukes so that they flee far off (Isaiah 17:13)
- a swarm of ruthless invaders that disappears in a single instant (Isaiah 29:5)
- a people whose loyalty burns off as fast as morning dew (Hosea 13:3)
The picture has two edges. One is worthlessness: chaff is the part nobody keeps. The other is sorting, since winnowing exists precisely to separate what is stored from what is thrown out, which is why Psalm 1 sets the chaff over against a tree planted by streams of water. Isaiah 41:15 turns the image around and hands the tool to Israel: God makes his people a threshing sledge that grinds mountains down until the hills themselves are nothing but chaff.
Two neighboring words are easy to confuse with it. Straw (תֶּבֶן) is the chopped stalk that was kept and put to work, fed to livestock and mixed into mud bricks. Stubble (קַשׁ) is what stands abandoned in the field after the harvest and is good only for burning. Chaff is the winnowing leftover, and unlike the other two it is never once put to any use at all.