Genesis 27 · a question people ask
Why couldn't Isaac take the blessing back?
Genesis doesn't explain. It records Isaac's words: "Yes, he will be blessed" (27:33), and "I have made him your lord… What then will I do for you, my son?" (27:37). Hebrews says, "By faith Isaac blessed Jacob and Esau, even concerning things to come" (Hebrews 11:20), and of Esau, "he found no place for a change of mind though he sought it diligently with tears" (Hebrews 12:17).
The verses
“Isaac trembled violently, and said, “Who, then, is he who has taken venison, and brought it to me, and I have eaten of all before you came, and have blessed him? Yes, he will be blessed.””
“Isaac answered Esau, “Behold, I have made him your lord, and all his brothers I have given to him for servants. I have sustained him with grain and new wine. What then will I do for you, my son?””
“By faith Isaac blessed Jacob and Esau, even concerning things to come.”
“For you know that even when he afterward desired to inherit the blessing, he was rejected, for he found no place for a change of mind though he sought it diligently with tears.”