Charles Spurgeon Commentary Hebrews 9:15-17

"And for this cause he is the mediator of a new covenant, that a death having taken place for the redemption of the transgressions that were under the first covenant, they that have been called may receive the promise of the eternal inheritance. For where a testament is, there must of necessity be the death of him that made it. For a testament is of force where there hath been death: for it doth never avail while he that made it liveth." — Hebrews 9:15-17 (ASV)

And for this cause he is the mediator of the new testament, that by means of death, for the redemption of the transgressions that were under the first testament, they which are called might receive the promise of eternal inheritance. For where a testament is, there must also of necessity be the death of the testator. For a testament is of force after men are dead: otherwise it is of no strength at all while the testator liveth.

Whether it is a covenant or a testament, death is necessary to make it valid. God's covenants have always been sanctioned and ratified with blood, and the covenant or the testament of eternal grace is ratified with the blood of the Surety and Testator.