Now the just shall live by faith: but if any man draw back, my soul shall have no pleasure in him. But we are not of them who draw back unto perdition; but of them that believe to the saving of the soul.Do you see how the author is making a categorical distinction here? We don't belong to the category of those who apostatize. Why? What's the distinction? The nature of belief. Some belief, as James says, is mere intellectual assent. The devils believe and tremble. But we are those who have the kind of faith that results in the saving of the soul. Very clear. Very consistent, even textbook consistent, with perseverance of the saints, per the Reformed view.
(Hebrews 10:38-39)
Then came Peter to him, and said, Lord, how oft shall my brother sin against me, and I forgive him? till seven times? Jesus saith unto him, I say not unto thee, Until seven times: but, Until seventy times seven.The servant is not greater than the master. If we are to forgive so many times over, will God be less gracious than us? God forbid. He will always be more gracious than we expect Him to be. Those who have sinned, despite knowing the truth, if they repent, and finally come to have the faith that saves, as Hebrews 10 teaches, they do NOT qualify for the warning of the passage. Only those who unrepentantly continue in their rebellion, because until they come to true repentance and true faith, there is nowhere they can go for atonement, if they refuse the once for all sacrifice of Jesus.
(Matthew 18:21-22)
Nonconcur; the author is not writing about salvation being a done deal for anyone (save those mentioned in the Roll Call of Faith. In fact he is rather careful to write that we are only saved if we obey the Messiah. For every high priest taken from among men is ordained for men in things pertaining to God, that he may offer both gifts and sacrifices for sins: Who can have compassion on the ignorant, and on them that are out of the way; for that he himself also is compassed with infirmity. And by reason hereof he ought, as for the people, so also for himself, to offer for sins. And no man taketh this honour unto himself, but he that is called of God, as was Aaron. So also Christ glorified not himself to be made an high priest; but he that said unto him, Thou art my Son, to day have I begotten thee. As he saith also in another place, Thou art a priest for ever after the order of Melchisedec. Who in the days of his flesh, when he had offered up prayers and supplications with strong crying and tears unto him that was able to save him from death, and was heard in that he feared; Though he were a Son, yet learned he obedience by the things which he suffered; And being made perfect, he became the author of eternal salvation unto all them that obey him; Called of God an high priest after the order of Melchisedec. Of whom we have many things to say, and hard to be uttered, seeing ye are dull of hearing. For when for the time ye ought to be teachers, ye have need that one teach you again which be the first principles of the oracles of God; and are become such as have need of milk, and not of strong meat. For every one that useth milk is unskilful in the word of righteousness: for he is a babe. But strong meat belongeth to them that are of full age, even those who by reason of use have their senses exercised to discern both good and evil.
Therefore leaving the principles of the doctrine of Christ, let us go on unto perfection; not laying again the foundation of repentance from dead works, and of faith toward God, Of the doctrine of baptisms, and of laying on of hands, and of resurrection of the dead, and of eternal judgment. And this will we do, if God permit. For it is impossible for those who were once enlightened, and have tasted of the heavenly gift, and were made partakers of the Holy Ghost, And have tasted the good word of God, and the powers of the world to come, If they shall fall away, to renew them again unto repentance; seeing they crucify to themselves the Son of God afresh, and put him to an open shame. For the earth which drinketh in the rain that cometh oft upon it, and bringeth forth herbs meet for them by whom it is dressed, receiveth blessing from God: But that which beareth thorns and briers is rejected, and is nigh unto cursing; whose end is to be burned. But, beloved, we are persuaded better things of you, and things that accompany salvation, though we thus speak. For God is not unrighteous to forget your work and labour of love, which ye have shewed toward his name, in that ye have ministered to the saints, and do minister. And we desire that every one of you do shew the same diligence to the full assurance of hope unto the end: That ye be not slothful, but followers of them who through faith and patience inherit the promises.
Hebrews, Catholic chapter five, in its entirety,
Hebrews, Catholic chapter six, Protestant verses one to twelve,
as authorized, but not authored, by King James