Matthew Henry Commentary Hebrews 10:26-31

"For if we sin wilfully after that we have received the knowledge of the truth, there remaineth no more a sacrifice for sins, but a certain fearful expectation of judgment, and a fierceness of fire which shall devour the adversaries. A man that hath set at nought Moses law dieth without compassion on [the word of] two or three witnesses: of how much sorer punishment, think ye, shall he be judged worthy, who hath trodden under foot the Son of God, and hath counted the blood of the covenant wherewith he was sanctified an unholy thing, and hath done despite unto the Spirit of grace? For we know him that said, Vengeance belongeth unto me, I will recompense. And again, The Lord shall judge his people. It is a fearful thing to fall into the hands of the living God." — Hebrews 10:26-31 (ASV)

The exhortations against apostasy and to perseverance are urged by many strong reasons. The sin here mentioned is a total and final falling away, when individuals, with a full and fixed will and resolution, despise and reject Christ, the only Saviour; despise and resist the Spirit, the only Sanctifier; and despise and renounce the gospel, the only way of salvation, and the words of eternal life. Of this destruction, God gives some notorious sinners, while on earth, a fearful foreboding in their consciences, with despair of being able to endure or escape it.

But what punishment can be more severe than to die without mercy? We answer, to die by mercy, by the mercy and grace which they have despised. How dreadful is the case when not only the justice of God, but his abused grace and mercy call for vengeance! All this does not in the least mean that any souls who sorrow for sin will be shut out from mercy, or that any who are willing to accept these blessings will be refused the benefit of Christ's sacrifice.

Him that cometh unto Christ, he will in no wise cast out.