Deuteronomy 17:16
14 When you come to the land the Lord your God is giving you and take it over and live in it and then say, “I will select a king like all the nations surrounding me,” 15 you must select without fail a king whom the Lord your God chooses. From among your fellow citizens you must appoint a king—you may not designate a foreigner who is not one of your fellow Israelites. 16 Moreover, he must not accumulate horses for himself or allow the people to return to Egypt to do so, for the Lord has said you must never again return that way. 17 Furthermore, he must not marry many wives lest his affections turn aside, and he must not accumulate much silver and gold.
Psalm 20:8
5 Then we will shout for joy over your victory; we will rejoice in the name of our God. May the Lord grant all your requests. 6 Now I am sure that the Lord will deliver his chosen king; he will intervene for him from his holy, heavenly temple, and display his mighty ability to deliver. 7 Some trust in chariots and others in horses, but we depend on the Lord our God. 8 They will fall down, but we will stand firm. 9 The Lord will deliver the king; he will answer us when we call to him for help!
Notes and References
"... Deuteronomy focuses much less on what the king must do than on what he must not do (17:16-17) ... These three restrictions “quite explicitly cut against the accepted pattern of kingship throughout the ancient Near East.” As Bible scholar Christopher Wright explains, “military power (the point of having great numbers of horses), the prestige of a large harem (frequently related to international marriage alliances), and great wealth (large amounts of silver and gold)—these were the defining marks of kings worthy of the title... But Deuteronomy starkly declares: ‘Not so in Israel.’” Why are weapons, wives, and wealth considered so dangerous? Cavalry and chariots signal a king’s self-glorification. When David’s sons Absalom and Adonijah seek to become king, each “provides himself with a chariot, horses, and fifty outrunners” (2 Samuel 15:1; 1 Kings 1:5). Moreover, massive military power can delude kings into thinking that they are “self-sufficient and not dependent on God.” Indeed, for the prophets, a massive chariot force is a sign of infidelity to God: Isaiah condemns the people because “their land is full of horses, and there is no limit to their chariots” (Isaiah 2:7) and Micah foresees a day when God “will destroy the horses in your midst and wreck your chariots” (Micah 5:10). Faithful followers of God, in contrast, declare: “They call on chariots, they call on horses, but we call on the name of the Lord our God” (Psalm 20:8) ..."
Held, Shai Give the People (Only Some of) What They Want: Deuteronomy and the King (pp. 1-10) Center for Jewish Leadership and Ideas, 2014