C. F. Keil and Franz Delitzsch on Ruth 1:2-4

Rth 1:2-4 אפרתים, the plural of אפרתי, an adjective formation, not from אפרים, as in Jdg 12:5, but from אפרת (Gen 48:7) or אפרתה (Rth 4:11; Gen 35:19), the old name for Bethlehem, Ephrathite, i.e., sprung from Bethlehem, as in 1Sa 17:12. The names - Elimelech, i.e., to whom God is King; Naomi (נעמי, a contraction of נעמית, lxx Νοομμείν, Vulg. Noëmi), i.e., the gracious; Machlon, i.e., the weakly; and Chilion, pining - are genuine Hebrew names; whereas the names of the Moabitish women, Orpah and Ruth, who were married to Elimelech’s sons, cannot be satisfactorily explained from the Hebrew, as the meaning given to Orpah, “turning the back,” is very arbitrary, and the derivation of Ruth from רעוּת, a friend, is quite uncertain. According to Rth 4:10, Ruth was the wife of the elder son Mahlon. Marriage with daughters of the Moabites was not forbidden in the law, like marriages with Canaanitish women (Deu 7:3); it was only the reception of Moabites into the congregation of the Lord that was forbidden (Deu 23:4).