Genesis 24:2-3

2Abraham had an important servant in his house. He had authority over everything that belonged to Abraham. Abraham said to him, ‘Come here and make a promise to me. Put your hand between my legs to show that I can trust you.

3You must make a serious promise to me in front of the Lord. He is the God who rules both heaven and earth. I am living among the Canaanite people, but you must promise this to me: Do not get a Canaanite woman to be a wife for my son.