John Gill Commentary Genesis 27:21

"And Isaac said unto Jacob, Come near, I pray thee, that I may feel thee, my son, whether thou be my very son Esau or not." — Genesis 27:21 (ASV)

And Isaac said to Jacob, come near, I pray you, that I may
feel you, my son
Still suspecting some fraud in the case; and whereas he knew that Esau was a hairy man, and Jacob smooth, he thought by feeling he could discover the imposture, if there was any: whether you are my very son Esau, or not ;
which he still pretty much questioned.