Genesis 26:34-35

When Esau was forty years old, he took as wives Judith the daughter of Beeri the Hittite, and Basemath the daughter of Elon the Hittite. And they were a grief of mind to Isaac and Rebekah. (Genesis 26:34, 35 NKJV)

Esau took wives from the people around him and they were a grief to Isaac and Rebekah. It is important who you marry. You are single handedly bringing someone foreign into the family. Their ideas may clash with e ideas of your family and strife ensues. Consider your family when you choose a spouse. If they don't get along, you have a lifetime of strife. But things were even more tumultuous back then. When Esau got married, he didn't move out, his wives moved in. This prompted Isaac and Rebekah to send Jacob back to Rebekah's family so he wouldn't choose a wife from the locals. (This doesn't mean that your family has to approve. It's better that God approves than your family. But keep it in mind.)