וַיָּ֤שֶׂם הָעֶ֙בֶד֙ אֶת־יָד֔וֹ תַּ֛חַת יֶ֥רֶךְ אַבְרָהָ֖ם אֲדֹנָ֑יו וַיִּשָּׁ֣בַֽע ל֔וֹ עַל־הַדָּבָ֖ר הַזֶּֽה׃
종이 이에 주인 아브라함의 환도뼈 아래 손을 넣고 이 일에 대하여 그에게 맹세하였더라
Chizkuni
תחת ירך אברהם, “under the thigh of Avraham.” Joseph, when asked by his father to swear that he would not bury him in Egypt but with his father and grandfather in Machpelah, did not do so, as he considered such behavior not respectful toward his father, even though he had requested him to swear. (Compare Genesis 47,2931)
Sforno
וישבע לו על הדבר הזה, he accepted all of Avraham’s conditions as part of his oath.