Genesis 27:12

my father peradventure will feel me, and I shall seem to him as a deceiver; and I shall bring a curse upon me, and not a blessing. This was partly prudence, partly the voice of conscience which told him that he would be making himself a scoffer in the eyes of his old blind father, one making sport of the latter's infirmity, and the discovery would result in his bringing away a curse instead of a blessing. Out of respect for his mother Jacob does not refer to the wrong itself, but to its dangerous consequences.