Deuteronomy 17:18-20

18 “And it shall be, when he sits on the throne of his reign, that he shall write for himself a copy of this Torah in a book, from the one before the priests, the Lĕwites.
19 And it shall be with him, and he shall read it all the days of his life, so that he learns to fear יהוה his Elohim and guard all the Words of this Torah and these laws, to do them,”
20 so that his heart is not lifted up above his brothers, and so as not to turn aside from the command, right or left, so that he prolongs his days in his reign, he and his children, in the midst of Yisra’ĕl.