Positive Mitzvah Seventeen

A King Must Write a Copy of the Torah for Himself

Devarim 17:18 It shall be that when he sits on the throne of his kingdom, he shall write for himself two copies of this Torah in a book, from before the Kohanim, the Leviim.

A Jewish king's royal treasury contains countless blocks of gold, beautifully embroidered bags filled with silver coins, diamonds, jewels and many glittering stones. These precious stones are locked away in vaults and the fortune is guarded by soldiers. But there is one precious item that the king will not entrust to anyone else. He refers to it constantly and always carries it with him. This is his own personal Torah Scroll. Hashem commands a Jewish King to write two Torah Scroll for himself...one to keep in his treasury and one to carry with him always. Thus, the Torah will guide him in ruling the Jewish people and creating a proper kingdom. (Rashi)

All the provisions of this Mitzvah are explained in Sanhedrin 2.

According to the 'Sefer Ha-Chinuch' this mitzvah was intended as a check upon the secular authority of the King. The Scroll of the Law which was to be written in his own name was calculated to impress upon him the supremacy of Divine Law as laid down in the Torah. It was to act as a constant reminder of his subservience to Hashem, and was therefore to accompany him at every turn:

Sanhedrin 21b

"When he goes forth to battle he shall take it forth with him, and when he returns he shall bring it back with him; when he sits in judgment it shall be with him, and when he sits at meat it shall be before him"