Boaz was a very wealthy man who lived in Bethlehem. When Naomi returned to Bethlehem with her widowed daughter-in-law, Ruth, she sent Ruth into the fields of Boaz to glean. Boaz learned that Ruth's deceased husband was a distant relative of his.
He acted kindly towards Ruth and instructed his farm workers to leave extra sheaves of barley for her to gather. Ruth had another relative of her late husband who was closer than Boaz.
By law, the other relative was obligated to marry Ruth and Boaz confronted the other relative with this law, and after the relative refused to marry Ruth, Boaz agreed to marry Ruth, and to buy the estate of Ruth's deceased husband.
After they got married, Ruth had a son named Obed, who became the father of Jesse, who became the father of David. Boaz and Ruth became the great-grandparents of King David.
Boaz means "strength." The story of Boaz is found in the Book of Ruth.