ולא ירבה לו נשים NEITHER SHALL HE
MULTIPLY WIVES TO HIMSELF only eighteen, for we find that David had six wives,
and it was announced to him (by Nathan the prophet): “[Thus saith the Lord … I
gave thy master’s wives into thy bosom] … and if that had been too little, I would
add unto thee such and such as these (i.e. twice as many)” (Sanhedrin 21a). (source)