Will burn up with unquenchable fire (katakausei puri asbestwi). Note perfective use of kata. The threshing floor, the fan, the wheat, the garner, the chaff (acuron, 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 verse Genesis 11 . The Messiah "will thoroughly cleanse" (diakaqariei, Attic future of -izw and note dia-). He will sweep from side to side to make it clean.