Rebecca apparently did not trust her husband. Even though she was told by God that Jacob was the one whom God would bless, she suspected that Isaac would bless Esau. She found out first hand what Isaac was planning, and made secret plans to thwart his actions. She also had spies in her household because they reported to her what Esau planned to do to his brother.

The real problem was she did not trust God, and took matters into her own hands. She felt that God somehow needed her help. Her actions definitely crossed the line, and caused deep family issues.

I really don't know how God would have worked out this problem if Rebecca had not intervened, but if there is one thing I have learned after 28 years of marriage it is that GOD does not need my help to work out his will. If I trust God, and do my best to obey His Word, then everything works out in the end. When I take control I just mess things up.

Genesis 27:1