Hebrews 9:15-17

Moffatt(i) 15 He mediates a new covenant for this reason, that those who have been called may obtain the eternal inheritance they have been promised, now that a death has occurred which redeems them from the transgressions involved in the first covenant. 16 Thus, in the case of a will, the death of the testator must be announced. 17 A will only holds in cases of death; it is never valid so long as the testator is alive.