Marriage, Abraham, Sarah, Hagar

There's much debate and confusion about the relationship between Abraham and Hagar and it's implications.

OLD TESTAMENT INSIGHTS
Gen. 16:3 identifies Hagar as Abram's WIFE (Strong's #802). She was also a servant to Sarah, but her status as a concubine didn't change the fact that she was just as married to Abram as Sarah was.
The same word used to refer to Sarah is also used to refer to Hagar.
Example:
Gen. 16:3a: "And Sarai, Abram's wife (802), took Hagar her female servant, the Mitsrite, and gave her to her husband Abram to be his wife (802)..."
It's also important to point out that the same Hebrew word 'ishshah (802) translates into English as both "wife" and "wives". There is no distinction between singular and plural in the original Hebrew text.
Example:
Gen. 2:24: "...and cleave to his wife (802)..."
Gen. 4:19: "And Lemek took for himself two wives (802)..."

Exodus 21:10: “If he takes another wife to himself, he shall not diminish the food, clothing, or marital rights of the first wife.”
Notice that God did not say "He may not marry another woman", but rather "IF he marries another woman".

Biblically, concubinage is not an immoral sexual relationship, similar to having a personal mistress. When the Hebrew word pilegesh (Strong's #6370) is used, it speaks of a female concubine that is MARRIED to her male partner.
*CLARIFICATION* While concubinage is not considered immoral, it is never recommended and typically it is only practiced by men of great wealth.


NEW TESTAMENT INSIGHTS
Since the OT defines na'aph (adultery) as a man laying with a married or betrothed woman (ie. a wife), Matt. 5:27-28 should read:
"You heard that it was said to those of old, 'You shall not commit adultery.' But I say to you that everyone looking at a gune (wife) to epithumeo (lust or covet) for her has already committed adultery with her in his heart."

If you read Matthew 19:4-6 or Mark 10:6-9, you'll see that Messiah wasn't addressing the issue of monogyny or polygyny (yes, the spellings are correct), He was answering a question about divorce. The entire point of this passage is the permanence of marriage. Nobody at the time, when hearing Messiah's words against divorce, would have been so confused as to think he was actually redefining marriage.

Romans 7:2-3: "Thus a married woman is bound by the law (Torah) to her husband as long as he lives; but if her husband dies, she is discharged from the law (Torah) concerning the husband. Accordingly, she will be called an adulteress if she lives with another man while her husband is alive. But if her husband dies, she is free from that law (Torah), and if she marries another man, she is not an adulteress."
This passage speaks VOLUMES, both in what it says and in what it DOES NOT say. If there were no other Scriptures teaching that a man may have multiple wives simultaneously, this one law teaches this truth. Clearly, God did not change His mind concerning polygyny in the NT.

Polygyny is not a popular concept today. Our "liberated" culture believes that "what's good for the goose is good for the gander", which is not a biblical principle.
While the vast majority of men should not engage in concubinage, that does not negate the fact that the bible allows for wise men with means to do so without condemnation.