Not true. Read Gen. 2:18-24. Note that all the parts I bolded are singular, not plural.
Monogamy is clearly the ideal; however, nowhere does either OT or NT condemn polygamy.
Like Jesus, I say that, even though David and Solomon were polygamous, “From the beginning it was not so.” (Mt 19:8)
He wasn’t answering a question about polygamy at all. It had nothing to do with David or Solomon, who never “put away” any of their wives. In fact, the original question had little to do with divorce, either:
3The Pharisees also came unto him, tempting him, and saying unto him, Is it lawful for a man to put away his wife for every cause?
From what I’ve read, the practice of “putting away” was a lot more like technically legal abandonment.
4And he answered and said unto them, Have ye not read, that he which made them at the beginning made them male and female,
5And said, For this cause shall a man leave father and mother, and shall cleave to his wife: and they twain shall be one flesh?
6Wherefore they are no more twain, but one flesh. What therefore God hath joined together, let not man put asunder.
Jesus utterly condemns this sort of abandonment. Then the Pharisees try to trap him by shifting the subject:
7They say unto him, Why did Moses then command to give a writing of divorcement, and to put her away?
A writ of divorcement left her free to marry again; “putting away” really didn’t.
That passage didn’t have anything to do with polygamy, but with dishonest breaking of marriage ties.
Monogamy’s clearly the ideal. However, the Scriptures leave polygamy open as an option. I do think churches ought to severely limit the sorts of people allowed to marry polygamously to a very narrow set. However, I can’t condemn the practice as a general rule, since Scripture doesn’t. I don’t honestly know what I’d do if someone I knew wanted to marry polygamously. It would probably take at least a year of serious conversations to convince me that the people involved could handle it. I’d have to do one big boatload of research on the practical aspects of the subject.