For the law having an outline of the about-to-be goods, not the image of the deeds themselves, each cycle with the same sacrifices that they perpetually offer, it is never able to complete the worshippers. Otherwise, would they not have ceased to be offered, no one having any more awareness of failures, the worshippers having once been purified? But in these is remembrance of failures every year, the blood of bulls and goats powerless indeed to cut off sins.
Therefore coming into the world, he says: Sacrifices and offerings you have not wished; but you have readied a body for me. Whole-burnings and those for failures you have not approved. Then I said, See! I have arrived to do your will, God; in the book's roll it is written about me.
Previously saying, Sacrifices and offerings and whole-burnings and those for failures, which are offered according to law, you have not wished or approved, he then adds, See! I have arrived to do your will. He abolishes the first so that the second might stand. By the willing we are consecrated, through the offering of the body of Jesus Christ, once.
And indeed every priest stands each day serving, and often offering the same sacrifices, which can never eradicate failures. But he, however, one having sacrificed for failures unto perpetuity, sat to the right of God, beyond that waiting until his enemies should be laid down, a footstool for his feet. For by one offering he has completed the consecrated unto perpetuity.
[Hebrews 10:1-14, my very rough translation. The author of Hebrews is discussing Jeremiah 31, an immensely important passage for early Christians, and very formative for Christian self-understanding. The manuscript tradition disagrees about whether the first sentence should be 'it [i.e., the law] is never able to provide completion' or 'they [i.e., the sacrifices] are never able to provide completion'. 'Failures' is more usually translated as 'sins', but practically speaking I think this passage has something broader in view. For instance, the sin-offerings ('those for failures' in the above translation) were offered not for what we usually think of as sins but for sins of ignorance and purely unintentional violations of the law. They are the sacrifices you'd offer if you accidentally broke the law and only later realized it, for instance. Given that they are twice mentioned in this passage, which as a whole is specifically about sacrifices not being able to complete, it seems reasonable to take the term to be used broadly here, including even unintended and accidental failures. These accidental failures don't play a large role in most of theology, but a way of reading the above passage is as saying that Christ's sacrifice provides a consecration so complete that it deals with even unintentional and accidental moral failures, for all time.
Famously, the book of Hebrews identifies four impossible things: it is impossible for those who wholly fall away to be restored (6:4); it is impossible for God to lie (6:18); it is impossible for blood sacrifices to remove failings (10:4, above); it is impossible to please God without faith (11:6). These can be seen, I think, as the essential conditions for the new covenant that constitutes Christian life.]
