Genesis 16:3
And Sarai Abram's wife took Hagar her maid the Egyptian, after Abram had dwelt ten years in the land of Canaan, and gave her to her husband Abram to be his wife.
Genesis 25:1
Then again Abraham took a wife, and her name was Keturah.
Even though they were his concubines, they were still his wives. A woman can be both concubine and wife at the same time.
And just remember the terminologies back then differed from today.
Lets get some real authority in here on this:
King James Dictionary
1. A woman who cohabits with a man, without the authority of a legal marriage; a woman kept for lewd purposes; a kept mistress.
2. A wife of inferior condition; a lawful wife, but not united to the man by the usual ceremonies, and of inferior condition. Such were Hagar and Keturah, the concubines of Abraham; and such concubines were allowed by the Roman laws.
http://www.studylight.org/dic/kjd/view. ... earch.y=19
A concubine has two meanings. And not the non wife status you chose.
Holman Bible Dictionary
CONCUBINE
A secondary wife. The taking of concubines dates back at least to the patriarchal period. Both Abraham and Nahor had concubines (Genesis 22:24; Genesis 25:6; 1 Chronicles 1:32). Concubines were generally taken by tribal chiefs, kings, and other wealthy men. Gideon had a concubine (Judges 8:31). Saul had at least one concubine, named Rizpah (2 Samuel 3:7; 2 Samuel 21:11). David had many (2 Samuel 5:13), but Solomon took the practice to its extreme, having 300 concubines, in addition to his 700 royal wives (1 Kings 11:3). Deuteronomy 17:17 forbid kings to take so many wives.
.
http://www.studylight.org/dic/hbd/view. ... earch.y=11
Proof the term differed back then than it did now.
ATS Bible Dictionary
CONCUBINE
A term which, in modern authors, commonly signifies a woman who, without being married to a man, lives with him as his wife;
but in the Bible the word concubine is understood in another sense- meaning a lawful wife, but of a secondary rank. She differed from a proper wife in that she was not married by solemn stipulation, but only betrothed; she brought no dowry with her, and had no share in the government of the family.
http://www.studylight.org/dic/ats/view. ... ion=Lookup
Your a perfect example of a modernized Christian. As modernism progresses so will Christianity in its ideology.
If you need more Christian Scholar quotes just ask I got alot more.