Isaiah 21:10
O my threshing, and the corn of my floor: that which I have heard of the LORD of hosts, the God of Israel, have I declared unto you. O my threshing, and the corn of my floor: that which I have heard of the LORD of hosts, the God of Israel, have I declared unto you.
God's people are his threshing and the corn of his floor, addressed as his threshing floor. Babylon itself is also the Lord's threshing floor where his judgment falls. The verse is a declaration to that threshing people of what was heard from the LORD of hosts, the God of Israel, heard by the watchman and made known to them. Its setting is the fall of Babylon.
God's judgment on Babylon brought down its idols and the religious system they upheld, ending that system's dominance and beginning its decline, though its worship continued in some places and sometimes influenced other beliefs. In the surrounding watchman scene, the heard message announces the morning and the coming King, with judgment and the raising of the dead accompanying his coming. The oracle connects with the signs of the times and the call for honest people to leave fallen Babylon. Applied to the church, the threshing-floor image means God uses affliction to thresh and purge his people, removing sin while strengthening grace and separating the person he loves from the sin he hates.