What now? The word covenant is clearly in the verse and in the context and in the OT text from which the author draws.
And forgiveness of sins was redemptive in the OT sacrifices although I can only find instances of sins committed in ignorance.
The author only claims the sacrifices could not cleanse the conscience of the sinner meaning the sinner while receiving forgiveness still retained his inner nature. The author claims the superior sacrifice of Christ will do what was prophesied in the OT regarding the circumcision of the heart into perfect understanding , obedience and after being absolved of the sins committed be rendered perfectly righteous and forever more guilt free. Not because the believer has a handy use when needed sacrifice in Christ but because the sinner sins no more.
There is in the OT an instance were the suffering servant is said to have taken the punishment of sinners onto himself.
Of course the concept is completely at odds with the legal prescription of the Law.
In fact the whole chapter could be used to support Christianity and yet their is hardly a mention of it in the NT..Isaiah 53:5
But he was pierced for our transgressions, he was crushed for our iniquities; the punishment that brought us peace was on him, and by his wounds we are healed.
http://www.biblegateway.com/passage/?se ... ersion=NIV
Maybe because it portrays the suffering servant as less than divine?