Even Sinners are Blessed
The Sassover Rabbi said: "It was the will of God that Jacob received the blessing from Isaac when he disguised himself as Esau. For had Isaac knowingly given his blessing to Jacob, it would be effective only when Jacob's descendants conduct themselves with the perfection of Jacob; whereas now the Israelites enjoy the blessing even when they sin, since Isaac intended to bless the sinful Esau."
Source: Fun Unzer Alten Olam
