Will burn up with unquenchable fire (katakausei puri asbestōi). Note perfective use of kata. The threshing floor, the fan, the wheat, the garner, the chaff (achuron, chaff, straw, stubble), the fire furnish a life-like picture. The “fire” here is probably judgment by and at the coming of the Messiah just as in Mat 3:11. The Messiah “will thoroughly cleanse” (diakathariei, Attic future of ̇izō and note diȧ). He will sweep from side to side to make it clean.