Deuteronomy 17:16-17

ERV(i) 16 Only 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.