Continuing the discussion of Christ as High Priest, the author of the letter speaks of the relationship between Him and the faithful as the essence of what the prophets of Israel called the new covenant. Indeed, the essence of any covenant-union consists...
Continuing the discussion of Christ as High Priest, the author of the letter speaks of the relationship between Him and the faithful as the essence of what the prophets of Israel called the new covenant. Indeed, the essence of any covenant-union consists, in the final analysis, in a person's sanctification by God, in the effect God has on a person, changing his spiritual life and sometimes even his nature. And the new union, that very new covenant first mentioned by Jeremiah, implied not only the Torah written in the heart, but also a measure of the Presence in the life of an individual person and of the people of God such as had never existed before.
This fullness of the Presence was connected with the person of the Savior, and therefore the author of the letter calls Him High Priest with a capital letter. But no measure of the Presence, even an absolute one, guarantees a person salvation, cleansing, sanctification, or anything else. A person is free, and in the final analysis everything is determined precisely by his choice.
The author of the letter reminds his readers that a sin committed consciously is irreparable in the sense that it is impossible to get rid of its consequences. It had always been so, and even Yahwistic purification offerings were powerless here, though God's presence at the Yahwistic altars was an unquestionable reality. The coming of Christ changes the situation qualitatively in this respect: now it is possible to be freed even from the consequences of sins once committed consciously, because, having entrusted himself to Christ, a person no longer stands alone before God with his sins.
Now Christ Himself is ready to help a person deal with the consequences of his sins, if only the person repents of what he has done and trusts his Savior. But if a person, having become a Christian, considers conscious sin possible for himself, this is equivalent to apostasy and denial of Christ, as the author of the letter reminds his readers.
And then returning back can become very, very difficult: by sinning consciously and of his own free will, a person is in fact opposing his Savior. The Savior is doing everything to free the person from the power of sin, while the person himself is at the same time handing himself over to sin's power, and doing so quite consciously. Such a life puts a wall between a person and Christ, even if previously that same person had turned to Christ quite sincerely and become His disciple. It is these foundational matters of Christian life that the author of the letter reminds his readers about.