The following is the results of your search for concubine.
Concubine: In the Bible denotes a female conjugally united to a man, but in a
relation inferior to that of a wife. Among the early Jews, from
various causes, the difference between a wife and a concubine was
less marked than it would be amongst us. The concubine was a wife of
secondary rank. There are various laws recorded providing for their
protection
(Exodus 21:7; Deuteronomy 21:10-14) and setting limits to the relation
they sustained to the household to which they belonged
(Genesis 21:14; 25:6)
They had no authority in the family, nor could they share in the
household government. The immediate cause of concubinage might be
gathered from the conjugal histories of Abraham and Jacob
(Genesis 16:1)ff
(Genesis 30:1)ff But in process of time the custom of
concubinage degenerated, and laws were made to restrain and regulate
it
(Exodus 21:7-9) Christianity has restored the sacred institution of
marriage to its original character, and concubinage is ranked with the
sins of fornication and adultery
(Matthew 19:5-9; 1 Corinthians 7:2)