During a famine, a man named Elimelech, and his wife Naomi, and their two sons, Mahlon and Chilion, moved from Bethlehem to Moab. After the death of Elimelech, his sons married two Moabite women named Orpah and Ruth. But their husbands later died and the two women were childless.
Naomi decided to return to Bethlehem and Ruth insisted on joining her, saying "Your people shall be my people, and your God my God" (Ruth 1:16).
In Bethlehem, Ruth met a man named Boaz, who was related to her late father-in-law. Boaz and Ruth got married. (Ruth 4:5). Ruth and Boaz had a son named Obed. Obed was the father of Jesse, and Jesse was the father of David. So Ruth was the great-grandmother of King David.
The life and times of Ruth are described in the Bible's book of Ruth, which part of the Old Testament of the Bible.