Hebrews 9:15-17 - Christ is the mediator of a new covenant

9:15

“For this reason ...” The writer has just described several ways in which Christ’s sacrifice and priesthood are infinitely superior to the Levitical sacrifices and priesthood. Christ is the mediator of a new covenant, the readers need to update their thinking. Under this new covenant those who are called receive the promised eternal inheritance. The word “promised” may be referring back to the Promised Land. The Promised Land was a temporal land. Is 65:17 and 66:22 refer to a new heaven and earth. So the Promised Land of the new covenant is so much greater than the Promised Land of the old covenant. “He has died as a ransom to set them free from the sins committed under the first covenant”. What about the believers of the Old Testament? Christ’s death applies retrospectively to them as well.  And the current readers may have been wondering about their sins committed under the old covenant, Christ’s death deals with those as well.

9:16,17

“In the case of a will ...” The word translated “will” is the same word translated “covenant” elsewhere in Hebrews. Now the Greek word does mean “last will and testament”, but is used in the LXX to refer to covenant. Gardener points out that the practice referred to here was not known in the Hellenistic world. Now it is obvious that someone has to die before a will comes into effect, but the death is taken as read, rather than needing to be proved. I cannot say I am totally convinced by all this, but the point is that it is the covenant rather than a will that is being talked about. It was ancient practice that covenants were enacted following the notional death of the covenant maker, represented by the death of an animal. So what the writer is saying is that the new covenant was not enacted until the death of Christ, so prior to that the Hebrews were indeed under the old covenant, but since the death of Christ the new covenant was not operational.