Deuteronomy 17:16,17 (KJV)
16 But he shall not multiply horses to himself, nor cause the people to return to Egypt, to the end that he should multiply horses: forasmuch as the Lord hath said unto you, Ye shall henceforth return no more that way.
17 Neither shall he multiply wives to himself, that his heart turn not away: neither shall he greatly multiply to himself silver and gold.
Deuteronomy 17:17 (KJV)
17 Neither shall he multiply wives to himself, that his heart turn not away.