The Book of Ruth in the Old Testament is much valued by Jews. It is about a Moabite young woman who elected to join her mother-in-law who moved back to Bethlehem after ten years in Moab. Ruth promised to follow Naomi's God and to love Him. Both the women were widows - Naomi was now too old to have children so held out no hope of finding an husband Ruth was much younger so able to bear children. A prince of Israel a kinsman of Naomi's dead husband named Boaz heard about Ruth and her decision to be a full proselyte and eventually married her saving her (and Naomi) from a lifetime of menial work in the fields. Thus a former pagan was chosen by God to become great-grandmother to David and part of the lineage of Jesus Christ.