After the encounter in Boaz’s field, we find another encounter between Boaz and Ruth in the following passage. Naomi tells Ruth where Boaz will be and what he is doing there. He is on the threshing floor, winnowing barley.
Ruth 3
2 Now, isn’t Boaz our relative, with whose daughters you were? Look, he is winnowing barley tonight on his threshing floor.
Winning
Before grain can be winnowed, it must first be threshed. Threshing loosens the kernels of wheat from the ears. Winnowing throws the grain into the air so that the wind carries away the chaff (the outer layer of the grain).
Winnowing grain, like circumcision, is a symbol of death and resurrection. The husk is removed and the new is revealed. The wind that carries away the chaff represents the spirit (John 3:8). In both Hebrew and Greek, the words for wind, breath, and spirit are the same: ruach (Hebrew) and pneuma (Greek). See also Ezekiel 37:9; Acts 2:2-4.
Israel
In the context of the book of Ruth, Boaz’s winnowing speaks of the work the Messiah will do for the faithful remnant of Israel in the future. The people will meet their Redeemer and be gathered outside the land in the wilderness. There He will enter into judgment with them (Ezek. 20:35), as He had previously done in the desert of Egypt (Ezek. 20:36). Israel will be purified (Ezek. 20:37-38), the wheat will be separated from the chaff.
in the night
But the winnowing also applies to us, believers from the nations. Boaz is winnowing in the night, a picture of the time in which we live and when the world is in darkness (Rom. 13:12). The time leading up to the meeting between Boaz and Ruth.
We are one with Christ, and He lifts us up so that we may seek the things that are above (Col. 3:1). It is God’s Spirit that blows away the chaff (Col. 3:5). That is the work of Christ in the present age: He cleanses us.