This can be stated in active form. Alternate translation: "his father, Isaac, refused to bless him" (See: [[rc://en/ta/man/translate/figs-activepassive]])
The abstract noun "repentance" can be translated with a verbal phrase. Alternate translation: "because it was not possible for him to repent" or "because it was not possible for him to change his decision" (See: [[rc://en/ta/man/translate/figs-abstractnouns]])