Genesis 27:19

And Jacob said unto his father, I [am] Esau thy firstborn,
&c.] Had he only said that he was his firstborn, he might have been excused from lying, because he had bought the birthright of Esau; but when he says, I am Esau, he can by no means be excused; for to say he impersonated Esau will not do; besides, he afterwards says he was his very son Esau, ( Genesis 27:24 ) : I have done according as thou badest me;
which is another lie; for Isaac had not bid him bring him any venison, nor go into the field for it, and take it and dress it for him; nor indeed had Jacob done either of these: arise, I pray thee, sit and eat of my venison;
or "hunting" ^F21, what he had hunted; another untruth, for it was not venison he brought him, nor anything that was hunted by him: by this it seems that Isaac lay upon a bed or couch through infirmity, and therefore is bid to arise and put himself in a proper posture for eating, which in those times and countries was usually sitting: that thy soul may bless me;
as this was the thing in view, so speaking of it as soon as he came in, and which he desired might be done after his father had eat and drank, might serve to take off the suspicion of his being another person; since this was what Isaac himself proposed to Esau to do; and this he said when there were none else present.