Biblegod doesn't "instruct" anyone to commit polygamy in the Bible. Poor choice of words by Quesi.
Nam, thank you, but I was hoping Quesi would answer. But thank you for confirming that the Bible does not instruct anyone to commit polygamy.
However, there are sections that do not state it is wrong to commit polygamy, and one could infer that it promotes their followers to do it, as long as they're male, and they love at least one of them (Exodus 21:10 is a good one,
This is in the context of when a girl is sold into slavery (can of worms - please start another thread if we have to go there) and the man she is sold to takes a wife for himself. This law provides for the man to not reduce her food, clothing, or even marital rights (if she wants to have intercourse, he is obliged to provide). This law is to protect women. It doesn't promote polygamy, anymore than the law regarding divorce was to promote divorce. Jesus said the law to protect a woman in a divorce was there because of the "hardness of their hearts." It's clear that that it wasn't promoting divorce, and it should be clear using context and rationale that Ex. 21:7-11 is for the protection of the woman.
“When a man sells his daughter as a slave, she shall not go out as the male slaves do. If she does not please her master, who has designated her for himself, then he shall let her be redeemed. He shall have no right to sell her to a foreign people, since he has broken faith with her. If he designates her for his son, he shall deal with her as with a daughter. If he takes another wife to himself, he shall not diminish her food, her clothing, or her marital rights. And if he does not do these three things for her, she shall go out for nothing, without payment of money. (Exodus 21:7-11, ESV)
and Deuteronomy 21:15 also a good one.
This again is a law to protect women, and not just Jewish women, but women taken as spoils of war. Should the Jewish man wish to take her as his wife, he has to wait a month before he can marry her and have sex with her. If he decides to divorce her, he has to let her go where she wants to go. He can not take a foreign wife as a spoil of war, then sell her as a slave, nor can he treat her as a slave.
“When you go out to war against your enemies, and the Lord your God gives them into your hand and you take them captive, and you see among the captives a beautiful woman, and you desire to take her to be your wife, and you bring her home to your house, she shall shave her head and pare her nails. And she shall take off the clothes in which she was captured and shall remain in your house and lament her father and her mother a full month. After that you may go in to her and be her husband, and she shall be your wife. But if you no longer delight in her, you shall let her go where she wants. But you shall not sell her for money, nor shall you treat her as a slave, since you have humiliated her. (Deuteronomy 21:10-14, ESV)
Both OT but Matt 5:17-18 validates those in the OT).
Yes, Jesus was validating the OT Law for Jews that He and the people He is addressing in the sermon were under until the time He fulfilled it.
But also note what Jesus said about divorce to see more about how it was not promoted, but tolerated, yet God made laws to protect the woman:
“It was also said, ‘Whoever divorces his wife, let him give her a certificate of divorce.’ But I say to you that everyone who divorces his wife, except on the ground of sexual immorality, makes her commit adultery, and whoever marries a divorced woman commits adultery. (Matthew 5:31-32, ESV)
And Pharisees came up to him and tested him by asking, “Is it lawful to divorce one's wife for any cause?” He answered, “Have you not read that he who created them from the beginning made them male and female, and said, ‘Therefore a man shall leave his father and his mother and hold fast to his wife, and the two shall become one flesh’? So they are no longer two but one flesh. What therefore God has joined together, let not man separate.” They said to him, “Why then did Moses command one to give a certificate of divorce and to send her away?” He said to them, “Because of your hardness of heart Moses allowed you to divorce your wives, but from the beginning it was not so. And I say to you: whoever divorces his wife, except for sexual immorality, and marries another, commits adultery.” (Matthew 19:3-9, ESV)