Luke has John give this menacing saying that can be found almost word for word in Matthew, chapter 3:12. Thus, this might be a Q source saying, since it is not found in Mark or John. Luke has God, the Lord, as a farmer at harvest time. Luke had John say that this famer has his winnowing fork ready in his hand (οὗ τὸ πτύον ἐν τῇ χειρὶ αὐτοῦ). He was going to clear the threshing floors (διακαθᾶραι τὴν ἅλωνα αὐτοῦ). He was going to gather his wheat into his barn or granary (καὶ συναγαγεῖν τὸν σῖτον εἰς τὴν ἀποθήκην αὐτοῦ). He would then burn up the leftover chaff (τὸ δὲ ἄχυρον κατακαύσει) with an everlasting or unquenchable fire (πυρὶ ἀσβέστῳ). This last phrase was a little different than that of Matthew. Nevertheless, this was a clear warning against the useless ones, who like chaff, would burn in an unstoppable fire.
Joel reminded the children of Zion that they should rejoice and be glad in Yahweh, their God, because he has given them plenty of rain, both the early and later rain, just like before the locust attack. Thus, the threshing floors would be full of grain. The vats or containers for the wine and the oil from the vines and trees would be overflowing.