וַיִּקְבְּר֨וּ אֹת֜וֹ יִצְחָ֤ק וְיִשְׁמָעֵאל֙ בָּנָ֔יו אֶל־מְעָרַ֖ת הַמַּכְפֵּלָ֑ה אֶל־שְׂדֵ֞ה עֶפְרֹ֤ן בֶּן־צֹ֙חַר֙ הַֽחִתִּ֔י אֲשֶׁ֖ר עַל־פְּנֵ֥י מַמְרֵֽא׃
그 아들 이삭과 이스마엘이 그를 마므레 앞 헷 족속 소할의 아들 에브론의 밭에 있는 막벨라 굴에 장사 하였으니
Rashi on Genesis
יצחק וישמעאל ISAAC AND ISHMAEL — From this we gather that Ishmael repented of his evil ways (cf.Bava Batra 16b) and yielded the precedence to Isaac. This is what is meant by the “good old age” mentioned in connection with Abraham (Genesis Rabbah 38:12).
Ramban on Genesis
AND HIS SONS ISAAC AND ISHMAEL BURIED HIM. In the language of Bereshith Rabbah,18062:6. “Here the son of the handmaid bestowed respect upon the son of the mistress” [since he yielded precedence to Isaac].
Radak on Genesis
ויקברו אותו יצחק וישמעאל בניו, seeing they were more honoured than his other sons and had been more beloved by him. This is why they took upon them themselves the procedures connected with their father’s burial even though the sons of Keturah were also in this region. Alternately, Avraham had already sent those sons away during his lifetime so that only Yitzchok and Ishmael remained in the region.