Adam Clarke on Genesis 28:1

And Isaac called Jacob - See note on Gen 27:46.

And blessed him - Now voluntarily and cheerfully confirmed to him the blessing, which he had before obtained through subtlety. It was necessary that he should have this confirmation previously to his departure; else, considering the way in which he had obtained both the birthright and the blessing, he might be doubtful, according to his own words, whether he might not have got a curse instead of a blessing. As the blessing now pronounced on Jacob was obtained without any deception on his part, it is likely that it produced a salutary effect upon his mind, might have led him to confession of his sin, and prepared his heart for those discoveries of God's goodness with which he was favored at Luz.