The Passuk uses identical: וֹשׁל ְנוֹת (expressions) by both the Melech and the Navi. They both need to be one of you; a brother and a: ק ְרוֹב relative from among you. Besides the simple Pshat (that a: רג ְ convert cannot be a Melech or a Navi) we can say a big Yesod. The Navi will give you Mussar, and the Melech is an example for you to follow. You cannot be expected to follow an act that you have no Shaychus with. Someone who is “up in the clouds” and has no Yetzer Hara, cannot be involved with your life. He has to be a person who understands you, and has been through similar Nisyonos. For good reason Dovid had to be an Admoni and a descendent of Mo'av. He had all those nasty Nisyonos and even worse than most people. Now you feel comfortable with “one of your own”; you can listen to him, and try to emulate him.
