"Then Isaac said to Jacob, 'Come near so I can touch you, my son, to know whether you really are my son Esau or not.' Jacob went close to his father Isaac, who touched him and said, 'The voice is the voice of Jacob, but the hands are the hands of Esau.' He did not recognize him, for his hands were hairy like those of his brother Esau; so he proceeded to bless him." NIV translation
Even though the voice did not match the touch, Isaac continued to bless Jacob. This is a picture of our struggle between flesh and spirit as our feelings can easily be deceived but our inner self will recognize the voice of God.
"'Are you really my son Esau?' he asked. 'I am,' he replied. Then he said, 'My son, bring me some of your game to eat so that I may give you my blessing.' Jacob brought it to him and he ate; and he brought some wine and he drank. Then his father Isaac said to him, 'Come here, my son, and kiss me.'" NIV translation
The doubts still linger in Isaac as he draws Jacob closer to him. This is a very sad family portrait as the deception continues.
"So he went to him and kissed him. When Isaac caught the smell of his clothes, he blessed him and said, 'Ah, the smell of my son is like the smell of a field that the Lord has blessed. May God give you heaven's dew and earth's richness - an abundance of grain and new wine. May nations serve you and peoples bow down to you. Be lord over your brothers, and may the sons of your mother bow down to you. May those who curse you be cursed and those who bless you be blessed.'" NIV translation
Isaac continued with the blessing and the first part involves the material blessing of productive fields. You can imagine Jacob waiting for him to get to the good part as he did not care about going out and working in a field. The second part involves power and authority which is what God had promised his mother that he would receive. The third part asks God to fight the battles for him as God is the one who brings curses and blessings.