"and so that he not turn aside from the mitzvah": even a "slight" mitzvah of a prophet. And thus is it written (I Samuel 13:13) "And Samuel said to Saul: You have acted foolishly. You have not kept the mitzvah, etc." "and so that he not turn aside from the mitzvah, right or left": even if he (seems to be) told that right is left and left is right.
"he and his sons": If he dies, his son succeeds him. This tells me only of a king. Whence do I derive (the same for) all of Israel's leaders? From "he and his sons in the midst of Israel" — All who are "in the midst of Israel" are succeeded by their sons.
R. Chanina b. Gamliel says: It is written (I Kings 3:13) "And also what you (Solomon) did not ask I have granted you — even riches and honor": I have granted you even what is not stipulated in the Torah. Shall I not then grant you what is written in the Torah (i.e., length of days, etc.) Only on condition that you observe the Torah, viz. (Ibid. 14) "If you (Solomon) walk in My ways to keep My statutes and My mitzvoth, as did your father David, then I shall prolong your days," and (Ibid. 9:4) "And as for you, if you walk before Me as your father David did, with wholeheartedness and uprightness, to do according to all that I have commanded you, to keep My statutes and My judgments, etc."
(דברים יז כ) לְבִלְתִּי רוּם לְבָבוֹ מֵאֶחָיו – וְלֹא מִשֶּׁל הֶקְדֵּשׁ.
(Devarim 17:20) "So that his heart not rise above his brothers": and not (not rise) above idolators.
וּלְבִלְתִּי סוּר מִן הַמִּצְוָה יָמִין וּשְׂמֹאול – שֶׁלֹּא יָסוּר מִן הַמִּצְוָה יָמִין וּשְׂמֹאול.
"and so that he not turn aside from the mitzvah": even a "slight" mitzvah of a prophet. And thus is it written (I Samuel 13:13) "And Samuel said to Saul: You have acted foolishly. You have not kept the mitzvah, etc." "and so that he not turn aside from the mitzvah, right or left": even if he (seems to be) told that right is left and left is right.
לְמַעַן יַאֲרִיךְ יָמִים עַל מַמְלַכְתּוֹ, אִם עוֹשֶׂה הוּא מַה שֶׁכָּתוּב בָּעִנְיָן – כְּדַי הוּא שֶׁיַּאֲרִיךְ יָמִים עַל מַמְלַכְתּוֹ.
"so that he prolong his days in his kingdom": If he does as is written here, he will be worthy of prolonging days in his kingdom.
הוּא וּבָנָיו – שֶׁאִם מֵת, בְּנוֹ עוֹמֵד תַּחְתָּיו. וְאֵין לִי אֶלָּא זֶה בִּלְבַד, מִנַּיִן לְכָל פַּרְנָסֵי יִשְׂרָאֵל שֶׁבְּנֵיהֶם עוֹמְדִים תַּחְתֵּיהֶם? תַּלְמוּד לוֹמַר: הוּא וּבָנָיו בְּקֶרֶב יִשְׂרָאֵל – כָּל שֶׁהוּא בְּקֶרֶב יִשְׂרָאֵל – בְּנוֹ עוֹמֵד תַּחְתָּיו.
"he and his sons": If he dies, his son succeeds him. This tells me only of a king. Whence do I derive (the same for) all of Israel's leaders? From "he and his sons in the midst of Israel" — All who are "in the midst of Israel" are succeeded by their sons.
רַבִּי חֲנַנְיָה בֶּן גַּמְלִיאֵל אוֹמֵר: הֲרֵי הוּא אוֹמֵר (מלכים א ג יג): ״גַּם אֲשֶׁר לֹא שָׁאַלְתָּ נָתַתִּי לָךְ גַּם עֹשֶׁר גַּם כָּבוֹד״ – עַל מַה שֶׁלֹּא הִתְנֵיתִי בַּתּוֹרָה לִתֵּן – נָתַתִּי לָךְ, עַל מַה שֶׁהִתְנֵיתִי לִתֵּן – אֵינִי נוֹתֵן לְךָ אֶלָּא אִם כֵּן עָשִׂיתָ, וְכֵן הוּא אוֹמֵר (מלכים א ג יד): ״וְאַתָּה אִם תֵּלֵךְ בִּדְרָכַי...״.
R. Chanina b. Gamliel says: It is written (I Kings 3:13) "And also what you (Solomon) did not ask I have granted you — even riches and honor": I have granted you even what is not stipulated in the Torah. Shall I not then grant you what is written in the Torah (i.e., length of days, etc.) Only on condition that you observe the Torah, viz. (Ibid. 14) "If you (Solomon) walk in My ways to keep My statutes and My mitzvoth, as did your father David, then I shall prolong your days," and (Ibid. 9:4) "And as for you, if you walk before Me as your father David did, with wholeheartedness and uprightness, to do according to all that I have commanded you, to keep My statutes and My judgments, etc."