Deuteronomy 17:17 "Neither shall he have too many wives"

The Jewish king must always concentrate on his people and their needs, always aiming to carry out his task of guiding the people in the ways of HaShem.

Having too many wives (In the past, people were allowed to have more than one wife), would surely distract him from his important duties.

The Torah forbids a Jewish king to marry more than the set amount of wives he is permitted to have.