Deuteronomy 17:15

“Thou shalt in any wise set [him] king over thee whom the Lord thy God shall choose, etc.] The Jews take this to be a command to set a king over them: whereas it is only a permission in case they should desire and determine on having one, as God foresaw they would; and this with a limitation and restriction to appoint none but whom God should choose, and which was their duty and interest to attend unto; for none could choose better for them, and was what he had a right unto, and it became them to submit to it, since he was their King in a civil and special sense, and another was only his viceregent; accordingly we find, when they expressed their desire to have a king in the time of Samuel,…”

“thou mayest not set a stranger over thee, which is not thy brother--that is, by their free and voluntary choice. But God, in the retributions of His providence, did allow foreign princes to usurp the dominion (Jer 38:17; Mat 22:17).”

“The king, like the judges and officers (compare Deuteronomy 16:18), is to be chosen by the people; but their choice is to be in accordance with the will of God, and to be made from among “their brethren.” Compare 1 Samuel 9:15; 1Sa 10:24; 1 Samuel 16:1; 1 Kings 19:16. Thou mayest not set a stranger over thee - The Jews extended this prohibition to all offices whatsoever (compare Jeremiah 30:21); and naturally attached the greatest importance to it: from where the significance of the question proposed to our Lord, “Is it lawful to give tribute to Caesar?” Matthew 22:17. A Gentile head for the Jewish people, which it was a principal aim of the Law to keep special and distinct from others, was…”

“Thy God shall chuse - Approve of, or appoint. So it was in Saul and David. God reserved to himself the nomination both of the family, and of the person. Thy brethren - Of the same nation and religion; because such a person was most likely to maintain true religion, and to rule with righteousness, gentleness, and kindness to his subjects; and that he might be a fit type of Christ their supreme king, who was to be one of their brethren. Deuteronomy 17:16”

“17:15 the man the Lord your God chooses: Human monarchy was not contrary to God’s will for Israel (cp. 1 Sam 8:6-7)—God promised Abraham and Sarah that their descendants would include kings (Gen 17:6, 16; see also Gen 35:11). But the abuses of kingship were condemned. The theology that views the Messiah in a kingly role (2 Sam 7:11-15; Pss 2; 110; Isa 9:6-7) provides for both human and divine royalty.”

“whom: Sa1 9:15-17, Sa1 10:24, Sa1 16:12, Sa1 16:13; Sa2 5:2; Ch1 12:23, Ch1 22:10, Ch1 28:5; Psa 2:2, Psa 2:6 from among: Jer 30:21; Mat 22:17 not set: Jer 2:25 Deuteronomy 17:16”