Ruth tells a compact, carefully constructed short story set against the chaotic backdrop of the judges era, though its own tone is quiet and domestic rather than violent: a famine drives an Israelite family to Moab, where the sons marry Moabite women before the men of the family all die, leaving the widow Naomi to return to Bethlehem accompanied by her equally widowed daughter-in-law Ruth, who refuses to leave her with the famous vow, "where you go I will go... your people shall be my people, and your God my God."
In Bethlehem Ruth gleans grain in the fields of Boaz, a wealthy relative of Naomi's late husband, and the story turns on the ancient Israelite practice of levirate obligation and land redemption, Ruth and Naomi engineering, with careful propriety, a legal claim on Boaz to marry Ruth and preserve the family line. The story closes by revealing its real stakes: the son born to Ruth and Boaz, Obed, becomes the grandfather of King David, making Israel's greatest king the direct descendant of a Moabite woman, from a people the Torah elsewhere treats with particular suspicion and even bars from full covenant membership. That genealogical twist, foreign ancestry sitting at the root of the Davidic line, gives the whole short book a quiet but pointed argument about who truly belongs to God's people.