Monogamy

Genesis 2:24  (NET Bible)

That is why a man leaves his father and mother and unites with his wife, and they become a new family.


Matthew 19:4-6  (NET Bible)

He answered, “Have you not read that from the beginning the Creator made them male and female,  and said, ‘For this reason a man will leave his father and mother and will be united with his wife, and the two will become one flesh’?  So they are no longer two, but one flesh. Therefore what God has joined together, let no one separate.”

 There are a number of Bible verses that speak about two becoming one flesh. Genesis 2:24 is the first occurrence of this phrase. Today we may read this as a clear teaching about monogamy. 

1 man + 1 woman = biblical marriage

However we should ask, did anyone in Bible times understand these verses the way we do.  Were the authors thinking about monogamy when they wrote it down?  Did anyone reading or listening take this as clear teaching that a man should only have sex with one wife?

It turns out it is hard to find examples of monogamous couples in the Bible.  Most of the main characters had multiple wives plus concubines. There was likely many lower class citizens who could only afford one wife, and many men who couldn't have any wives.  But seems monogamy was not promoted as the ideal by any of the Old Testament leaders or prophets. 

I suspect in that context they read these verses more like: Wife #1 + man = one flesh. Wife #2 + man = one flesh. Concubine #1 + man = one flesh. Slave girl + man = one flesh.... and so on.  They lived in a time and place where there were many valid combinations where two could become one flesh.

It turns out monogamy was introduced by the Roman culture, not by the Jews or Christians. 

"Marriage in ancient Rome was a strictly monogamous institution: a Roman citizen by law could have only one spouse at a time. The practice of monogamy distinguished the Greeks and Romans from other ancient civilizations, in which elite males typically had multiple wives." https://en.wikipedia.org/wiki/Marriage_in_ancient_Rome