The answer is: She had looked after Naomi

Ruth 2:10-11

In the unfolding story of Ruth, we’re introduced to a stunning display of loyalty and kindness, particularly through Ruth's unwavering support for her mother-in-law, Naomi. When Ruth chooses to accompany Naomi back to Bethlehem after the deaths of their husbands, it’s a remarkable testament to their relationship—a bond forged through shared loss and love. Boaz sees this dedication, and it's this very quality that compels him to allow Ruth to glean in his fields.

Culturally, gleaning was more than just finding leftover crops; it was a crucial social practice where those with means left part of their harvest for the poor and marginalized. It's fascinating to note that Boaz, by being generous and compassionate towards Ruth, lives up to the ethics outlined in the Law of Moses, specifically Leviticus 19:9-10, which commands not to strip your field bare and to allow the poor to gather food.

Boaz becomes a prime example of a "kinsman redeemer," a role crucial in Israelite history, which reflects a deep-rooted value of community responsibility. His willingness to engage with Ruth, and to safeguard her safety while gleaning, resonates with themes of generosity prevalent throughout the Hebrew Bible.

This account is not just about personal charity but highlights a communal obligation to care for one another, reminding us that kindness, backed by principled actions, creates pathways for redemption and new beginnings. And as we learn later, this story is larger than Ruth and Boaz—it's one of lineage that eventually leads to King David, intertwining family and faith in profound ways.