Thematic Bible: Not to make unholy connections for them

Then Isaac called Jacob and blessed him and charged him, saying, Thou shalt not take a wife of the daughters of Canaan. Arise, go to Padanaram to the house of Bethuel, thy mother's father, and take thee a wife from there of the daughters of Laban, thy mother's brother.

And Abraham was old and well stricken in age, and the LORD had blessed Abraham in all things. And Abraham said unto his eldest slave of his house, who ruled over all that he had, Put, I pray thee, thy hand under my thigh, and I will make thee swear by the LORD, the God of the heavens and the God of the earth, that thou shalt not take a wife unto my son of the daughters of the Canaanites, among whom I dwell; read more.
but thou shalt go unto my country and to my kindred and take a wife unto my son Isaac.