Genesis 28:6-9

Esau learned that Isaac had blessed Jacob and sent him to Northwest Mesopotamia to find a wife there. He also learned that Isaac had commanded Jacob not to marry a Canaanite woman and that Jacob had obeyed his father and mother and had gone to Northwest Mesopotamia. So Esau saw that his father Isaac did not want his sons to marry Canaanite women. Now Esau already had wives, but he went to Ishmael son of Abraham, and he married Mahalath, Ishmael’s daughter. Mahalath was the sister of Nebaioth.