A concubine is still the wife of the man to whom she is married. The only difference between what was called a "wife" and a "concubine" is that the offspring of the concubines were not entitled to the inheritance.
Come on, folks. Get a clue.
BTW
"Get a clue"? Are you serious?
Let's take a look at Abraham to get the
real answer here.
He had a wife, Sarai. She encouraged him to take a concubine Hagar.
Genesis 17:
18 And Abraham said to God, If only Ishmael might live under your blessing! 19 Then God said, Yes, but your wife Sarah will bear you a son, and you will call him Isaac. I will establish my covenant with him as an everlasting covenant for his descendants after him. 20 And as for Ishmael, I have heard you: I will surely bless him; I will make him fruitful and will greatly increase his numbers. He will be the father of twelve rulers, and I will make him into a great nation. 21 But my covenant I will establish with Isaac...
So God recognized Isaac as the true heir, and blessed Ishmael only because Abraham asked. That would tell me that God was not going to even recognize the concubine's son. She was not much and her son was not even going to be recognized without the father's request.
Genesis 21:
9 But Sarah ... said to Abraham, Get rid of that slave woman [you notice she didn't say "wife"] and her son, for that womans son will never share in the inheritance with my son Isaac.
11 The matter distressed Abraham greatly because it concerned his son. 12 But God said to him, Do not be so distressed about the boy and your slave woman [not wife]. Listen to whatever Sarah tells you, because it is through Isaac that your offspring[b] will be reckoned. 13 I will make the son of the slave into a nation also, because he is your offspring. [I would say this was a favor from God who was Abraham's friend.]
Basically, this makes Hagar nothing at all (a slave), and God didn't bless Ishmael because of her. She was a "slave woman" and nothing.
Genesis 25
1 Abraham had taken another wife, whose name was Keturah.
His later "wife" ended up being called a "concubine" when it came to her children's inheritance. She also was not a wife according to God. And those people caused the rightful son's heirs trouble too.
Genesis 25:
5 Abraham left everything he owned to Isaac [the rightful heir]. 6 But while he was still living, he gave gifts to the sons of his concubines and sent them away from his son Isaac to the land of the east.
I would imagine he did this to avoid conflicts. However, you will notice that the conflicts between Israel today are with the concubines' children that is Hagar and Keturah--referred to in the Bible as "concubines."
Does this in any way give you a clue that having multiple wives will result in suffering for your sons who are from your wife? And if so, then we might conclude that a "concubine" is not properly had--not God's will.
There were no other wives. There was one wife and "concubines" that created great trouble, and still are, for the rightful heir.
I would also ask you if Jesus' ancestry came from a concubine--either his stepfather's or mother's? No! He descended from Abraham's wife.
I believe we must conclude that a wife and her child or children are the ones who have rights, and the concubines' children have only what is given them as a result of the father's generosity. God didn't recognize them as heirs.
But we still need to recognize that the Lord Jesus said, "It was not that way from the beginning..." From the beginning, it was one man and one woman. It was from greed that the Lord agreed to give any man another wife.
If the successive women were important, they would have been in the line of Jesus. They were not. In fact, the line of Jesus came from the oldest son on both sides. So not only is the inheritance specific to a wife, it is specific to the oldest son.
(Interesting fact: Jesus' line came down from Bathsheba on both sides: I Chron 3:
3b Shammua, Shobab, Nathan (Joseph's ancestor) and Solomon (Mary's ancestor). These four were by Bathsheba daughter of Ammiel).