"He said to the chief servant in his household, the one in charge of all he had, “Put your hand under my thigh. I want you to swear by the Lord, the God of heaven and the God of earth, that you will not get a wife for my son from the daughters of the Canaanites, among whom I am living,"
Genesis 24:2-3—Abraham making his servant promise to get Isaac a good wife. Guess that’s how they did it back in the day.