God gave David and Solomon many wives and concubines.
They were completely without sin in these matters (except for the case of Uriah and his wife).
David also received many wives and concubines, and also Solomon and Moses my servants, as also many others of my servants, from the beginning of creation until this time; and in nothing did they sin save in those things which they received not of me.
David's wives and concubines were given unto him of me, by the hand of Nathan, my servant, and others of the prophets who had the keys of this power; and in none of these things did he sin against me save in the case of Uriah and his wife. Doctrine and Covenants 132:38-39
Orihah was a righteous king and he had 31 children. (Which is hard to do with one wife.)
Orihah did execute judgment upon the land in righteousness ... And he begat sons and daughters; yea, he begat thirty and one, among whom were twenty and three sons. Ether 7:1-2
It's an abomination to God.
And now it came to pass that the people of Nephi, under the reign of the second king, began to grow hard in their hearts, and indulge themselves somewhat in wicked practices, such as like unto David of old desiring many wives and concubines, and also Solomon, his son. Jacob 1:15
Behold, David and Solomon truly had many wives and concubines, which thing was abominable before me, saith the Lord. Jacob 2:24
Wherefore, my brethren, hear me, and hearken to the word of the Lord: For there shall not any man among you have save it be one wife; and concubines he shall have none. Jacob 2:27
For behold, he did not keep the commandments of God, but ... he had many wives and concubines. Mosiah 11:2
Riplakish did not do that which was right in the sight of the Lord, for he did have many wives and concubines. Ether 10:5