As for proof I thought the subject so well established that you would be able to do your own research. Since you did not, I will provide a starting point.
While there is no evidence of a polyandrous state in primitive Jewish society, polygamy seems to have been a well-established institution, dating from the most ancient times and extending to modern days. The Law indeed regulated and limited this usage; and the prophets and the scribes looked upon it with disfavor. Still all had to recognize its existence, and not until late was it completely abolished. At no time, however, was it practiced so much among the Israelites as among other nations; and the tendency in Jewish social life was always toward MONOGAMY.
The Jewish Encyclopedia, s.v. "Polygamy," Vol. X, pages 120-122 available at
http://jewishencyclopedia.com/view.jsp?artid=425&letter=P&search=polygamy
Further evidence can be found in Some Sephardi and Mizrahi Jews (particularly those from Yemen and Iran, where polygamy is a social norm) who discontinued polygamy much more recently, and the State of Israel had to make provisions for polygamous families immigrating after its 1948 creation, though new polygamous marriages are forbidden in Israel. Once again showing that polygamy was common enough to need to be addressed in law in the modern world.
At issue is not that polygamy is the norm ... rather the question as original posed, is it a Christian (and through subsequent debate, Jewish) practice. Jews have been and continue to practice polygamy. No it is not common, no it is not custom, but non the less, it is practiced.
No scripture ever states that having more than one wife is a sin. It falls into that area of actions that make it difficult to keep ones hart on God. Like the story of the rich man who asked Jesus what must he do to have riches in heaven. When Jesus told him to sell everything and follow him, he was showing that the man's hart was not on God but rather his wealth. Likewise, a polygamist is choosing a much harder road to follow. But it is not impossible for a wealthy man to be saved just more difficult.
As for the divorce issue, you are correct, the Talmud allows for divorce for just about any reason and thus, many Jews throughout history have practiced "serial polygamy" - Divorcing one woman to marry another. I postulate that the permissive divorce law created and currently supports this state of serial polygamy and is still practiced in the Jewish (and Christian) community today.
The passage reads:
Then Nathan said to David, "You are the man! This is what the LORD, the God of Israel, says: 'I anointed you king over Israel, and I delivered you from the hand of Saul. 8 I gave your master's house to you, and your master's wives into your arms. I gave you the house of Israel and Judah. And if all this had been too little, I would have given you even more. 9 Why did you despise the word of the LORD by doing what is evil in his eyes? You struck down Uriah the Hittite with the sword and took his wife to be your own. You killed him with the sword of the Ammonites. 10 Now, therefore, the sword will never depart from your house, because you despised me and took the wife of Uriah the Hittite to be your own.'
The following points are made in the passage:
1) The Lord God is making the following statement
2) God anointed David King of Israel
3) God then recites his blessings
- delivery from the hands of Saul
- gave him his masters house
- gave him his masters wives into his arms (sexual relations)
- gave him the house of Judea and Israel
4) God then says that had this not been enough, he would have given him even more
5) Then God asks why David turned away from God and did evil
- killing Uriah and taking his wife
- the evil God chastens David with is NOT POLYGAMY
- the evil God accuses is murder, lust, greed, marrying a Hittite (against Jewish law), and perhaps worse, despising God
"Late" - not until after the Second Temple period.
As I said in my post, the practice of polygamy which had been abandoned for centuries was revived in the Islamic period as a way of fitting in.
No scripture ever states that having more than one wife is a sin.
It's clear that polygamy - like divorce - was a concession made to man's weakness in the preMessianic period, not a sin but not a laudable practice either.
Not only does Jesus describe marriage as being between a man and a woman, but he sets aside divorce as a no-longer-acceptable concession to man's weakness.
The New Testament, whenever it discusses marriage, assumes monogamy as the underlying standard.
Christians have never practiced polygamy and never accepted it as permissible.
For a Christian to permit it or engage in it would be a complete repudiation of the highest historical standards of Christian behavior as practiced from the apostolic age down to this.