TT #87 · Parashas Shoftim · Second Aliyah · Passuk 17:15
You shall surely set over yourself a king whom the Eternal your God will choose; from among your brethren you shall set a king over yourself; you may not place over yourself a foreigner who is not your brother.
Torah Temimah points to Sifrei Devarim 157.
TT lemma: מִקֶּרֶב אַחֶיךָ.
English: ‘From among your brethren you shall set a king over yourself’ – all appointments that you make shall be only from among your brethren.
Derash expanding the scope (Sifrei) — the limitation ‘from among your brethren’ applies to every public appointment, not only the king.
No public office of authority in Yisrael may be given to a foreigner. The rule that applies to the king applies to all appointments of power.