God established that three of His seven commanded appointed times (feast days) – First Fruits, Pentecost, and Tabernacles – would be associated with two different grain harvests and one fruit of the vine harvest that took place annually in Israel. Moreover, God established that these three crops (barley, wheat, and grapes) would also depict, spiritually speaking, three classes of people. The Barley represents the holy and saintly overcomers, the Wheat represents the carnal believers, and the Grapes mostly represent the unsaved unbelievers.
Every crop of grain or fruit must experience a time of separation. When the crop is ripe, it is harvested by separating the chaff or the refuse. Thus, mature barley goes through a time of separation or winnowing. Using a wooden fork or “fan,” winnowers throw the gathered barley against the wind so that the wind can separate the chaff (husk) from the grain. On the other hand, mature wheat goes through a time of separation or crushing/threshing. Using a tribulum, a wooden board with holes in it, or using a wooden sled, which oxen often pull, threshers stand or sit on the board or sled as it is drawn over the grain that is laying on the threshing floor, causing the grain to be separated from the husk (chaff) and straw. Lastly, the mature grapes also go through a time of separation or crushing (treading). Using a winepress, treaders crush the grapes until the grapes’ juice is separated from the grapes’ skins, which results in the pressed juice running into the vats.