Polygamy: Forbidden
Source: Nav
Deuteronomy 17:17
He must not take many wives for himself, lest his heart go astray. He must not accumulate for himself large amounts of silver and gold.
Leviticus 18:18
You must not take your wife’s sister as a rival wife and have sexual relations with her while your wife is still alive.
Malachi 2:14, 15
Yet you ask, “Why?” It is because the LORD has been a witness between you and the wife of your youth, against whom you have broken faith, though she is your companion and your wife by covenant. / Has not the LORD made them one, having a portion of the Spirit? And why one? Because He seeks godly offspring. So guard yourselves in your spirit and do not break faith with the wife of your youth.
Matthew 19:4, 5
Jesus 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 be united to his wife, and the two will become one flesh’?
Mark 10:2–8
Some Pharisees came to test Him. “Is it lawful for a man to divorce his wife?” they inquired. / “What did Moses command you?” He replied. / They answered, “Moses permitted a man to write his wife a certificate of divorce and send her away.”
1 Timothy 3:2, 12
An overseer, then, must be above reproach, the husband of but one wife, temperate, self-controlled, respectable, hospitable, able to teach, / A deacon must be the husband of but one wife, a good manager of his children and of his own household.
Titus 1:6
An elder must be blameless, the husband of but one wife, having children who are believers and who are not open to accusation of indiscretion or insubordination.