Genesis 24:5

2 And 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:

3 And I will make thee swear by the LORD, the God of heaven and the God of the earth, that thou wilt not take a wife for my son of the daughters of the Canaanites among whom I dwell:

4 But thou shalt go to my country, and to my kindred, and take a wife for my son Isaac.

5 And 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 whence thou camest?

6 And Abraham said to him, Beware that thou bring not my son thither again.

7 The 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 I will give this land: he will send his angel before thee, and thou shalt take a wife for my son from thence.

8 And if the woman shall not be willing to follow thee, then thou shalt be clear from this my oath; only bring not my son thither again.