John Trapp on Isaiah 21:10

Ver. 10. O my threſhing, and the corn of my floor] That is, O my Church and people, whom by ſo many tribulations I have hitherto been threſhing, that I might ſunder thee from the chaff, and make thee the corn of the floor, or,Non ut perdam, ſed ut probem & purgem. Frumentum Dei ſum, &c. Ignat. as the Hebrew here hath it, my ſon of the floor, and may lay thee up as pure grain in my Garner. See chap. 28.27.

That which I have heard from the Lord of Hoſts] viz. That you my poor Country-men ſhall be threſhed for a while, and winnowed by Babylon (ſee chap. 25.10 & 41.15. Jer. 51.33. Mic. 4.13.) Ʋt cum triturando è gluma, & follibus ſuis utriculiſ que triticum educitur, and that you ſhall at length be delivered from this grievous affliction: all this you may write upon as certain and infallible. I have herein told you not the dreams of mine own heart, but the very undoubted words of God himſelf.