Deut 17:20

לְבִלְתִּ֤י רוּם־לְבָבוֹ֙ מֵֽאֶחָ֔יו וּלְבִלְתִּ֛י ס֥וּר מִן־הַמִּצְוָ֖ה יָמִ֣ין וּשְׂמֹ֑אול לְמַעַן֩ יַאֲרִ֨יךְ יָמִ֧ים עַל־מַמְלַכְתּ֛וֹ ה֥וּא וּבָנָ֖יו בְּקֶ֥רֶב יִשְׂרָאֵֽל׃ ס

Then his heart will not be exalted above his countrymen, and he will not turn aside from the commandment, to the right or to the left, in order that he and his sons may reign many years over his kingdom in Israel.