The answer is: Winnowing barley

Ruth 3:2

At the threshing floor, Boaz was winnowing barley, which means he was separating the grain from the chaff. This process would typically take place after harvest time, so it was a bustling time for rural communities. In the agricultural world of ancient Israel, threshing floors were pivotal, not just for grain processing but also as places of social chatter. Imagine it: farmers gathering, sharing stories, and perhaps even making important life's decisions while surrounded by golden barley!

The act of winnowing symbolizes not just the physical separation of elements but a deeper spiritual concept too. The chaff, seen as unwanted fluff, is compared to things that do not serve a purpose in one’s spiritual life. The story of Ruth resonates so powerfully because it's all about redemption—of relationships, standing in society, and even a re-evaluation of purpose. Boaz, immediately recognizable as a symbol of kinship and protection, illustrates how love and duty can intertwine.

Additionally, the mention of barley is not trivial; barley was significant in ancient cultures and appears repeatedly in the Bible, establishing staple food themes, sacrificial connections, and even as part of stories of abundance, such as with Jesus’ miracle of feeding the 5,000, where barley loaves were used. The imagery of harvesting and divine provision intertwines beautifully, linking both Ruth and Jesus’s ministry on themes of abundance and sustenance. Thus, Boaz becoming a protector and provider stands out in a deeper narrative spanning generations.