Boaz said Ruth had come to take refuge under whose wings?

Answer: The LORD, the God of Israel

Boaz blessed her: "May you receive a rich reward from the LORD, the God of Israel, under whose wings you have taken refuge."

“May the LORD repay your work, and may you receive a rich reward from the LORD, the God of Israel, under whose wings you have taken refuge.””— Ruth 2:12 (BSB)