Among the Hebrews a concubine occupied a position in the nature of a secondary wife and was sometimes spoken of as a wife. It appears that concubines were slave girls, one of three kinds: (1) a Hebrew girl sold by her father (Ex 21:7-9), (2) a foreign slave girl purchased, or (3) a foreign girl captured in warfare (De 21:10-14). Some were the slave girls or handmaids of the free wife, as in the cases of Sarah, Leah, and Rachel.​—Ge 16:3, 4; 30:3-13; Jg 8:31; 9:18.

Concubinage was in existence before the Law covenant and was recognized and regulated by the Law, which protected the rights of both wives and concubines. (Ex 21:7-11; De 21:14-17) Concubines did not have all the rights in the household that the regular wife had, and a man might have a plurality of wives along with concubines. (1Ki 11:3; 2Ch 11:21) In cases where the wife was barren, she sometimes gave her handmaid to the husband as a concubine, and the child born of the concubine would then be considered as the child of the free wife, her mistress. (Ge 16:2; 30:3) Sons of concubines were legitimate and could inherit.​—Ge 49:16-21; compare Ge 30:3-12.

Since by Oriental custom the wives and concubines of a king could only become those of his legal successor, Absalom, who demonstrated the greatest disrespect for David, tried to strengthen his efforts to get the kingship by having relations with the ten concubines of his father David. (2Sa 16:21, 22) After King Solomon was enthroned, Adonijah, an older brother of Solomon, who had already made an attempt for the kingship, approached Solomon’s mother, Bath-sheba, saying: “You yourself well know that the kingship was to have become mine,” and then asked her to request of Solomon, Abishag the Shunammite, who appears to have been viewed as a wife or a concubine of David. Solomon angrily answered: “Request also for him the kingship,” and then he ordered that Adonijah be put to death, indicating that he construed Adonijah’s request as an effort to get the kingdom.​—1Ki 1:5-7; 2:13-25.

God did not see fit to restore the original standard of monogamy as he had established it in the  garden of Eden until the appearance of Jesus Christ, but he did protect the concubine by legislation. Concubinage logically worked toward a more rapid increase of the population in Israel.​—Mt 19:5, 6; 1Co 7:2; 1Ti 3:2; see MARRIAGE (Polygamy).

Figurative Use. The apostle Paul likens Jehovah to the husband of a free wife, the “Jerusalem above,” who is the “mother” of spirit-begotten Christians, as Abraham was husband to Sarah. He compares the relationship of Jehovah to the nation of Israel represented by its capital city Jerusalem to that of a husband and a concubine. Through the Law covenant Jehovah was ‘married’ to Jerusalem as a “servant girl,” a ‘concubine,’ analogous to the relationship of Abraham to the slave girl and concubine Hagar.​—Ga 4:22-29; compare Isa 54:1-6.