First, from the Book of Mormon, Jacob 2:23-24:

23“For behold, thus saith the Lord:
This people begin to wax in
INIQUITY; they understand NOT
the scriptures, for they seek to
excuse them- selves in committing
WHORE- DOMS, because of the
things which were written concern
ing David, and Solomon his son.
24“Behold, David and Solomon truly
had many wives and concubines,
which thing was ABOMINABLE
BEFORE ME, saith the Lord.”

And, second, from the D&C, Sec.132

1 “Verily, thus saith the Lord…you
have inquired of my hand to know
and understand wherein I, the Lord,
justified my servants…David
and Solomon,…as touching the
principle and doctrine of - having
many wives and
concubines . . . 39 David’s wives
and concubines were given unto
him of me,…”