Genesis 27:33

Isaac trembled very exceedingly Being perplexed and astonished to consider herein God's overruling providences, and how strangely his purpose of giving the blessing to Esau had been disappointed. Those that follow the choice of their own affections, rather than the dictates of the divine will, involve themselves in such perplexities as these. But he soon recovers himself, and ratifies the blessing he had given to Jacob; I have blessed him, and he shall be blessed He might have recalled it; but now, at last, he is sensible he was in an error when he designed it for Esau. Either recollecting the divine oracle, or having found himself more than ordinarily filled with the Holy Ghost when he gave the blessing to Jacob, he perceived that God did, as it were, say Amen to it.

Genesis 27:35. Thy brother hath taken away thy blessing That which by birthright belonged to thee, and which I had fully resolved to have bestowed on thee. He took away my birthright This was a false accusation, for he himself had sold it, and despised it, Hebrews 12:16. This shows there was yet no true repentance in him.