Hebrews 8 tells us that the priesthood of Christ is superior to the priesthood of Aaron because the covenant that Christ mediates is a better covenant (v. 6). The new covenant is not better than the old one because it has different promises. Rather, it is a better covenant because as the new covenant, God no longer gives incomplete revelation through His prophets but has come to earth in the person of Jesus Christ to complete His revelation directly (1:1–3a).
But even though the promises of the old covenant and the new covenant are fundamentally the same, there was a “problem” with the old covenant. In some senses, it was lacking. This is made clear in 8:7, which tells us that “if that first covenant had been faultless, there would have been no occasion to look for a second.” The old covenant had faults. It was only a provisional administration. This is not to say that the old covenant did not reveal God’s perfection. After all, the Law is “holy and righteous and good” (Rom. 7:12).
In what sense then do we find fault with the old covenant? The faults can be seen in a variety of complementary ways. The first has already been suggested in previous studies, namely, the incompleteness of the old covenant revelation (Heb. 1:1–2). In Christ we have a faultless covenant because He fulfills and transcends all that is found in the old covenant. He is the reality, only seen under the administration of the old covenant in a provisional and shadowy form.
A second fault found in the old covenant results from its provisional nature. John Owen comments on this verse that “the discussion is not about whether the first covenant was in itself holy, just, good, and in every way perfect as far as its own goals were concerned. If nothing more were required of the old covenant and it could have completely sanctified the church, it would have been perfect. But it was not, as it had never been designed for this purpose.” In other words, the old covenant did achieve its goal, for the goal of the Law was never to bring perfection. Rather, its goal was to point us to the one who would bring perfection, and it was faultless in achieving that goal (Gal. 3:24). But fault is found with the old covenant because the hope for perfection does not compare to the new covenant reality of the perfection that Christ will finally bring to the world.
It is tempting to think that old covenant saints found the life of faith much easier to live than we do. However, as we have seen, the days of prophets and kings had only an incomplete and provisional revelation. If you are tempted to think that the days of old were better, remember that we live in the day of more full revelation.