Speaking about Christian life, the author of the letter recalls ancient prophecies whose meaning comes down to the fact that the messianic age is the age of universal redemption and forgiveness of sins. He understands perfectly well that nothing of the kind can be achieved by the partial purification that traditional Yahwist purifying sacrifices could provide. Something must happen that will qualitatively change the situation with purification. And this something must undoubtedly be connected with the Person of the One who brought the Kingdom into the world. Thus the image takes shape of what is usually called the redemptive sacrifice of Christ.
The issue, of course, is not ransom in the sense in which we usually understand that word today, not that God buys someone back from the devil, paying for the redeemed with the life of His Son. The issue is redemption in the sense in which purifying sacrifices in the Old Testament books are sometimes called redemptive: they free a person from the power of sin, partially and for a time, at the cost of God's intervention and the death of the animal offered in sacrifice, which, of course, is in no way guilty of the sins of those who are freed from them through the sacrifice being offered. So Christ too takes upon Himself the consequences of the sins we have committed, and for this He comes into the fallen world, which in the end kills Him. And He consents to being killed, although He is, of course, in no way guilty of the sins whose consequences He takes upon Himself, and indeed has no part in any sin at all.
Yet without such cleansing intervention, the fullness of sanctification will remain inaccessible to fallen humanity, just as the Kingdom will remain inaccessible. Christ voluntarily gives up His life, goes to death, sacrifices Himself in order to intervene in the situation connected with our sins, in order to deal in our place with the consequences of what we have done, because we ourselves will never be able to deal with those consequences. This is the sense in which both Paul and his disciple, the author of the Letter to the Hebrews, speak of redemptive sacrifice.
