Genesis 24:2-9

2So Abraham instructed the chief servant of his household, who managed all he owned, “Place your hand under my thigh, 3and I will have you swear by the LORD, the God of heaven and the God of earth, that you will not take a wife for my son from the daughters of the Canaanites among whom I am dwelling, 4but will go to my country and my kindred to take a wife for my son Isaac.”

5The servant asked him, “What if the woman is unwilling to follow me to this land? Shall I then take your son back to the land from which you came?”

6Abraham replied, “Make sure that you do not take my son back there. 7The LORD, the God of heaven, who brought me from my father’s house and my native land, who spoke to me and promised me on oath, saying, ‘To your offspring I will give this land’—He will send His angel before you so that you can take a wife for my son from there. 8And if the woman is unwilling to follow you, then you are released from this oath of mine. Only do not take my son back there.”

9So the servant placed his hand under the thigh of his master Abraham and swore an oath to him concerning this matter.