Genesis 24:2-9

24:2 Abraham said to his servant, the senior one in his household who was in charge of everything he had, “Put your hand under my thigh 24:3 so that I may make you solemnly promise by the Lord, the God of heaven and the God of the earth: You must not acquire a wife for my son from the daughters of the Canaanites, among whom I am living. 24:4 You must go instead to my country and to my relatives to find a wife for my son Isaac.”

24:5 The servant asked him, “What if the woman is not willing to come back with me to this land? Must I then take your son back to the land from which you came?”

24:6 “Be careful never to take my son back there!” Abraham told him. 24:7 “The Lord, the God of heaven, who took me from my father’s house and the land of my relatives, promised me with a solemn oath, ‘To your descendants I will give this land.’ He will send his angel before you so that you may find a wife for my son from there. 24:8 But if the woman is not willing to come back with you, you will be free from this oath of mine. But you must not take my son back there!” 24:9 So the servant placed his hand under the thigh of his master Abraham and gave his solemn promise he would carry out his wishes.