For a will takes effect only at death, since it is not in force as long as the one who made it is alive.
In these verses the apostle considers the gospel under the notion of a will or testament, the new or last will and testament of Christ, and shows the necessity and efficacy of the blood of Christ to make this testament valid and effectual. I. The gospel is here considered as a testament, the new and last will and testament of our Lord and Saviour Jesus Christ.
Commenting on Hebrews 9:15-22
For a testament is of force after men are dead,.... The necessity of Christ's death is here urged, from the nature and force of a testament or will, among men, which does not take place, and cannot be executed, till a man is dead.
Verse 17. For a testament. Such an arrangement as God enters into with man. See the remarks on . Is of force. Is ratified, or confirmed--in the same way as a deed or compact is confirmed by affixing a seal. After men are dead. επινεκροις.