Genesis 24:2-9

2And Abraham said to his eldest servant of his house, that ruled over all that he had, Put, I pray thee, thy hand under my thigh: 3And I will make thee swear by the LORD, the God of heaven, and the God of the earth, that thou shalt not take a wife for my son of the daughters of the Canaanites, among whom I dwell: 4But thou shalt go to my country, and to my kindred, and take a wife for my son Isaac. 5And the servant said to him, It may be the woman will not be willing to follow me to this land: must I needs bring thy son again to the land from which you came? 6And Abraham said to him, Beware that thou bring not my son there again. 7The LORD God of heaven, who took me from my father’s house, and from the land of my kindred, and who spoke to me, and who swore to me, saying, To thy seed will I give this land; he shall send his angel before thee, and thou shalt take a wife for my son from there. 8And if the woman will not be willing to follow thee, then thou shalt be clear from this my oath: only bring not my son there again. 9And the servant put his hand under the thigh of Abraham his master, and swore to him concerning that matter.