18 So he went in to his father and said, "My father." And he said, "Here I am. Who are you, my son?" 19 Jacob said to his father, "I am Esau your firstborn. I have done as you told me; now sit up and eat of my game, that your soul may bless me." 20 But Isaac said to his son, "How is it that you have found it so quickly, my son?" He answered, "Because the Lord your God granted me success." 21 Then Isaac said to Jacob, "Please come near, that I may feel you, my son, to know whether you are really my son Esau or not." 22 So Jacob went near to Isaac his father, who felt him and said, "The voice is Jacob's voice, but the hands are the hands of Esau." 23 And he did not recognize him, because his hands were hairy like his brother Esau's hands. So he blessed him. 24 He said, "Are you really my son Esau?" He answered, "I am."
Matthew Henry's Commentary on Genesis 27:18-24
Commentary on Genesis 27:18-29
(Read Genesis 27:18-29)
Jacob, with some difficulty, gained his point, and got the blessing. This blessing is in very general terms. No mention is made of the distinguishing mercies in the covenant with Abraham. This might be owing to Isaac having Esau in his mind, though it was Jacob who was before him. He could not be ignorant how Esau had despised the best things. Moreover, his attachment to Esau, so as to disregard the mind of God, must have greatly weakened his own faith in these things. It might therefore be expected, that leanness would attend his blessing, agreeing with the state of his mind.