"And Isaac and Ishmael his sons buried him" (Genesis 25:9). The son of the maidservant gave honor to the son of the mistress. Anyone of whom "expiring" and "being gathered" are said - this refers only to the death of the righteous. But behold, of Ishmael "expiring" and "being gathered" are written (Genesis 25:17)! Ishmael repented. As it is written, "And Isaac and Ishmael his sons buried him." Now since Ishmael was the elder, what is the reason that Isaac is reckoned before him? Learn from this that he repented and put Isaac ahead of himself. But perhaps Scripture lists them in order of wisdom? If so, then where it is written, "And Esau and Jacob his sons buried him" (Genesis 35:29), there too it lists them in order of wisdom? Rather, from the fact that it placed the other one first and led him ahead, learn from this that he repented.
Ishmael Repented and Yielded Honor to Isaac at Abrahams Grave
Yalkut Shimoni on Torah 110:7
(בראשית כה ט) וַיִּקְבְּרוּ אוֹתוֹ יִצְחָק וְיִשְׁמָעֵאל בָּנָיו, בֶּן הָאָמָה חוֹלֵק כָּבוֹד לְבֶן הַגְּבִירָה. כָּל מִי שֶׁנֶּאֱמַר בּוֹ גְּוִיעָה וַאֲסִיפָה אֵינוֹ אֶלָּא מִיתָתָן שֶׁל צַדִּיקִים. וְהָא יִשְׁמָעֵאל כְּתִיב בֵּיהּ (להלן פסוק יז) גְּוִיעָה וַאֲסִיפָה, יִשְׁמָעֵאל עָשָׂה תְּשׁוּבָה, דִּכְתִיב וַיִּקְבְּרוּ אוֹתוֹ יִצְחָק וְיִשְׁמָעֵאל בָּנָיו, מִכְדֵי יִשְׁמָעֵאל קָשִׁישׁ, מַאי טַעְמָא חָשִׁיב לֵיהּ יִצְחָק מִקַּמֵּיהּ, שְׁמַע מִנָּהּ תְּשׁוּבָה עָבִיד וְאַדְבְּרֵיהּ [לְ]יִצְחָק לְקַמֵיהּ. וְדִלְמָא דֶּרֶךְ חָכְמָתָן קָא חָשִׁיב. אֶלָּא מֵעַתָּה דִּכְתִיב (בראשית לה, כט) "וַיִּקְבְּרוּ אֹתוֹ עֵשָׂו וְיַעֲקֹב בָּנָיו" הָכָא נַמִּי דֶּרֶךְ חָכְמָתָן קָא חָשִׁיב, אֶלָּא מִדְּאַקְדְּמֵיהּ וְאַדְבְּרֵיהּ שְׁמַע מִנָּהּ עָשָׂה תְּשׁוּבָה.