Matthew Henry on Genesis 26:34-35

Esau was foolish in marrying two wives together, and still more in marrying Canaanites, strangers to the blessing of Abraham, and subject to the curse of Noah. It grieved his parents that he married without their advice and consent. It grieved them that he married among those who had no religion. Children have little reason to expect God's blessing who do that which is a grief of mind to good parents.