פירוש על ברכות 69:4

That hillulim refers to the benediction before and after fruits.

That Lev. xix. 24 refers to all fruit of the fourth year and not to the vine only; consequently the second deduction from hillulim need not be used to prove that only the vine requires redemption, but can be used to show that a benediction is required when partaking of fruits.

Since the second deduction from hillulim is required to prove that only the vine required redemption, how does he show that a benediction is required when partaking of fruits?