What does Ruth 4:13 mean?

When Boaz first met Ruth, he respected her sacrifice for Naomi so much that he prayed a blessing on her: "The LORD repay you for what you have done, and a full reward be given you by the LORD, the God of Israel, under whose wings you have come to take refuge!" (Ruth 2:12). Two months later, when Ruth proposed to Boaz, she said, "Spread your wings over your servant" (Ruth 3:9), challenging Boaz to be the agent of his own blessing. Boaz agreed to do what he could do. God honors both their choices.

This is one of only two mentions that God acts directly in the story of Naomi and Ruth; the first was when He lifted the famine in Bethlehem (Ruth 1:6). Fertility of the land and of humans is in God's hand. Every other choice and act that led to this moment came from people whose hearts are inclined to God's will.

This is God's normal way of interacting with humans. We may wish for His divine intervention for our safety, or blessing, or even convenience. We may pray that He perform miracles for the sake of His work. He does want us to rely on Him and trust Him to provide, but He also invites us into His work. He wants to work with and through us.

God gave Israelites food. Naomi made the choice to return to Bethlehem. Ruth made the choice to come with her and plan for her care. Boaz made the choice to join Ruth in her work. God completed the work by giving a son. Through human choices and God's work, that son led to King David who led to Jesus the Messiah (Matthew 1:1–16). If God had not invited Ruth into His work and she had not responded—if He had used more traditional family lines—we wouldn't have had this story about lovingkindness, self-sacrifice, family loyalty, and a Moabite woman in the line of the Savior of the world.