Most of our English Bible versions translate Hebrews 9:16-17 this way (I have provided vv.15 and 18 for context):
And for this reason He is the Mediator of the new covenant, by means of death, for the redemption of the transgressions under the first covenant, that those who are called may receive the promise of the eternal inheritance. 16 For where there is a testament, there must also of necessity be the death of the testator. 17 For a testament is in force after men are dead, since it has no power at all while the testator lives. 18 Therefore not even the first covenant was dedicated without blood. (NKJV, vv. 16-17 are in italics)
Or the ESV:
Therefore he is the mediator of a new covenant, so that those who are called may receive the promised eternal inheritance, since a death has occurred that redeems them from the transgressions committed under the first covenant. 16 For where a will is involved, the death of the one who made it must be established. 17 For a will takes effect only at death, since it is not in force as long as the one who made it is alive. 18 Therefore not even the first covenant was inaugurated without blood. (ESV vv.16-17 in italics)
With the translation diatheke as either “testament” or “will” the reader is led to conclude that these verses are not talking about the new covenant. In verse 15 the Greek word diatheke is translated as “covenant.” The same translation (“covenant”) is repeated in v.18.
If I were to give all the occurrences of diatheke in Hebrews you would see that, apart from 9:16 and 17 the word is uniformly translated “covenant.” One doesn’t have to think hard about why this word is rendered as “covenant” in these 16 other instances. The contexts make it very clear that the writer is referring, either to the Mosaic Covenant or Law, or to the New Covenant which replaces it. And one doesn’t have to seek too far for proof of this. Hebrews 9:15 contrasts the “first covenant” with the “new covenant,” as does verse 18. The chapter itself reinforces the contrast and the appropriate translation “covenant.”
Why translate diatheke, which has been expressed as “covenant” everywhere else in the Book, as “testament” or “will” in vv.16-17? The answer is because it has been assumed that “the death of the one who made it” refers to a “testator” as per a modern “Last Will and Testament.” For we all know that when a person makes a will it only comes into force when they are dead. Thus, one writer stated,
In the New Testament the diatheke as a ‘last will’ is once brought into connection with the sacrifice of Christ… – Geerhardus Vos, “Hebrews, the Epistle of the Diatheke,” in The Princeton Theological Review, Vol. 13, No.4, , 601.
But is he right? What is it in the context which demands the switch from “covenant” to “testament,” other than this assumption that a will is being referred to simply because of “the death of the one who made it”? It seems to me that the whole case depends upon the supposition that diatheke can only mean “last will and testament” in Hebrews 9:16-17. There are several reasons for believing this to be a faux pas:
1. The meaning of diatheke in Hebrews 9:15 is “covenant.” This is clear because the writer is referencing the Mosaic “covenant” in the preceding verses (vv.11-13). If the word meant “last will and testament” in v.15 the connection with the Mosaic Covenant in vv.11-13 would be lost and the writer’s whole argument rendered suspect. Such a switch would create an equivocation within the argument. That is, it would have the author mean two things by one word in a confusing way. This problem comes into sharp relief once chapter 8 is considered. The superiority of the “better covenant” (e.g. Heb. 8:6) demands it be contrasted with the Mosaic Covenant, and hence, that it be itself a true covenant and not a last will and testament. This understanding is assured by the contrast in 8:7 which see. Following on from this, Hebrews 8:8-12 gives the longest quotation of the OT by any NT writer. Is this quotation to do with a testament or a covenant? The answer is impossible to ignore. It is to a “covenant” (OT “berith“), not a testament!
2. But secondly, the meaning “covenant” makes perfect sense. George H. Guthrie, an acknowledged expert on Hebrews, writes:
Interpreters often have read 9:16-17 in terms of “will” or “testament,” but these verses should be read, in their context, as speaking of the establishment of a covenant… “The one arranging [diatithemi] it,” occurring in participial form, in 9:16-17, refers to the sacrificial animal that must die for a covenant to be established… This fits perfectly with the argument of 9:18-22, which deals with Moses’ inauguration of the Sinai covenant with the sprinkling of blood (Exod.24:3-8). – in G. K. Beale & D. A. Carson, editors, Commentary on the New Testament Use of the Old, 973.
3. When one adds to this the critical observations of P. T. O’Brien this position is weakened yet further. O’Brien’s full discussion can be found on pages 328-332 of his recent The Letter To The Hebrews (in the Pillar series). I shall condense his argument below using several quotes:
a. “As we have seen, the context of v.15 seems to demand the sense of ‘covenant’ because only covenants have mediators[underlining mine], while in v.18 mention is made of the ‘first diatheke‘, namely, the Sinai event and hence can only be a covenant.”
b. “What our author says in vv.16-17 does not correspond to any ‘any known form of Hellenistic (or indeed any other) legal practice.’ A Hellenistic will was secure and valid when it was written down, witnessed and deposited, not when the testator died. Further, the distribution of the estate could occur when the testator was still living.”
Indeed, don’t we see this very thing in the Parable of the Prodigal Son, where the son took his inheritance before the father had died?
c. The wider context of Hebrews with our author’s view of inheritance and his emphasis on the cult appears incongruous with the model of the secular Hellenistic testament.
from Peter. T. O’Brien, The Letter To The Hebrews, Pillar (2010), 329-330
We conclude from all this evidence, both internal and external, that there is no good reason for translating diatheke as “testament” in the sense of “last will and testament” in Hebrews 9:16-17. Thus, we commend the following translation of these verses as given below:
“For where a covenant is, there must of necessity be the death of the one who made it. 17 For a covenant is valid only over the dead, for it is never in force while the one who made it [the one who must die] lives.”