Bereishit (Genesis) 23:17-24:9
17And Ephron’s field, which was in Machpelah, facing Mamre, the field, and the cave within it, and all the trees in the field, within all its surrounding boundaries, was confirmed 18as Avraham’s as a purchase in the view of the children of Heth, among all who came to the gate of the city. 19And afterwards Avraham buried Sarah his wife in the cave of the field of Machpelah facing Mamre, which is Hebron in the land of Canaan. 20Thus, the field with its cave was confirmed as Avraham’s as an estate for a burial site, from the children of Heth.
1Now Avraham was old, well on in years, and HaShem had blessed Avraham with everything. 2And Avraham said to his servant, the elder of his household who controls all that is his: “Place now your hand under my thigh. 3And I will have you swear by HaShem, G-d of heaven and G-d of earth, that you not take a wife for my son from the daughters of the Canaanites, among whom I dwell. 4Rather, to my land and to my kindred shall you go and take a wife for my son for Yitzchak.”
5The servant said to him: “Perhaps the woman shall not wish to follow me to this land; shall I take your son back to the land from which you departed?” 6Avraham answered him, “Beware not to return my son to there. 7HaShem, G-d of heaven, Who took me from the house of my father and from the land of my birth: Who spoke concerning me, and who swore to me saying, ‘To your offspring will I give this land,’ He will send His angel before you, and you will take a wife for my son from there. 8But if the woman will not wish to follow are you, you shall then be absolved of this oath of mine. However, do not return my son to there.”
9So the servant placed his hand under the thigh of Avraham his master and swore to him regarding this matter.