His fan - The word used here and rendered “fan” means a winnowing shovel instead. It was used for throwing the grain, after it was threshed, into the air, so that the chaff might be driven away by the wind. This mode of separating the grain from the chaff is still practiced in the East. It is not probable that the fan, as the term is now used, was known to the Orientals as an instrument for cleaning grain. See the notes at Isaiah 30:24.
His floor - The threshing-floor was an open space, or area, in the field, usually on an elevated part of the land, Genesis 50:10. It had no covering or walls. It was a space of ground 30 or 40 paces in diameter, and made smooth by rolling it or treading it hard. A high place was selected for the purpose of keeping it dry, and for the convenience of winnowing the grain by the wind. The grain was usually trodden out by oxen. Sometimes it was beaten with flails, as with us; and sometimes with a sharp threshing instrument, made to roll over the grain and to cut the straw at the same time. See the notes at Isaiah 41:15.
Shall purge - Shall cleanse or purify. Shall remove the chaff, etc.
The garner - The granary, or place to deposit the wheat.
Unquenchable fire - Fire that shall not be extinguished, that will utterly consume it. By the floor, here, is represented the Jewish people. By the wheat, the righteous, or the people of God. By the chaff, the wicked. They are often represented as being driven away like chaff before the wind, Job 21:18; Psalms 1:4; Isaiah 17:13; Hosea 13:13. They are also represented as chaff which the fire consumes, Isaiah 5:24. This image is often used to express judgments, Isaiah 41:15; “Thou shall thresh the mountains and beat them small, and shalt make the hills as chaff.” By the unquenchable fire is meant the eternal suffering of the wicked in hell, 2 Thessalonians 1:8-9; Mark 9:48; Matthew 25:41.