Kabbalah zu Bereschit 27:7

Come and behold, When Isaac said to Esau "and go out to the field, and catch me some venison (Heb. צָיִדה)" (Beresheet 27:3), with a Hei, instead of using tzayid, without a Hei. This has already been explained. And Esau went (hunting) to be blessed by Isaac, who said to him "and bless you before Hashem" (Ibid. 7). It would have been well to say just "and I will bless you," but since he added "before Hashem," the Throne of Glory of the Holy One, blessed be He, then trembled and said, Could it be, that the serpent is freed from these curses, and Jacob remains subject to them?