Deuteronomy 17:15-17

Amplified Bible

¹⁵ you shall most certainly set a king over you whom the Lord your God chooses. You shall set a king over you from among your countrymen (brothers); you may not choose a foreigner [to rule] over you who is not your countryman. ¹⁶ Further, he shall not ^[a]acquire many [war] horses for himself, nor make the people return to Egypt in order to acquire horses [to expand his military power], since the Lord said to you, ‘You shall never return that way again.’ ¹⁷ He shall not acquire multiple wives for himself, or else his heart will turn away [from God]; nor [for the same reason] shall he acquire great amounts of silver and gold.