What did Isaac think about this plan?
It is likely he never learned about it. On his deathbed, Isaac, blind and feeble, called Esau to him. Isaac told Esau to go out and hunt game and prepare a meal for him so he could bless Esau before he died. Rebekah overheard this. She urged her favorite son, Jacob, to act in Isaac’s stead. So Jacob dressed as Esau, even going so far as to put goatskin on his hands and neck to mimic his brother’s hairiness. Isaac said, “How is that you have found it so quickly my son?” Jacob answered, “Because the Lord your God granted me success.” (NRSV, Genesis 27:20) Jacob’s wording suggested that he did not believe in God yet, or at any rate, he believed in other gods as well. That was about to change.
Isaac thought Jacob was Esau, and gave Jacob the blessing that belonged to the oldest son. Esau, when he learned this, wailed, “Have you only one blessing, father? Bless me, also, father!” (NRSV, Genesis 27:38)
Isaac realized that Jacob had deceived him, but according to the custom of the time, could not retract the blessing he had given. Isaac blessed Esau as well, but it was bittersweet: “Your dwelling will be away from the earth’s richness, away from the dew of heaven above. You will live by the sword and you will serve your brother. But when you grow restless, you will throw his yoke from off your neck.” (NIV, Genesis 27:39–40) After that, Esau planned to murder Jacob, so Jacob left the area.