Hebrews 9:15-17

Therefore, he is the mediator of a new covenant, so that those who are called might receive the promise of the eternal inheritance, because a death has taken place for redemption from the transgressions committed under the first covenant. Where a will exists, the death of the one who made it must be established. For a will is valid only when people die, since it is never in effect while the one who made it is living.