One that hath despised (rather, set at naught) Moses' Law dieth without mercy under (i.e. at the word of) two or three witnesses. The reference is to Deuteronomy 17:2-7, as shown by the mention of the "two or three witnesses" (Deuteronomy 17:6). The sin there spoken of is that of one who "hath wrought wickedness in the sight of the LORD, in transgressing his covenant, and hath gone and served other gods, and worshipped them, either the sun, or the moon, or any of the host of heaven." The significance of this in its bearing on the meaning of ἁμαρτανόντων in verse 26 has been already noted.
Of how much sorer punishment, suppose ye, shall he be thought worthy, who hath trodden underfoot 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? It has been already remarked how these very strong expressions (answering to those in Hebrews 6:6) further denote the kind of sin. intended by ἁμαρτανόντων in Hebrews 10:26. Three characteristics of it are given:
Citations from the Old Testament follow, according to the general plan of the Epistle, to show that there is a terrible as well as a gracious side of the revelation of the God of Israel, and especially (as intimated by the second quotation) that his own people may be the objects of his vengeance. For we know him that said, Vengeance belongeth unto me, I will recompense, saith the Lord. And again, The Lord shall judge his people. Both citations are from Deuteronomy 32:35, Deuteronomy 32:36, the second being introduced also into Psalms 135:14. The first is remarkable as a combination of the texts of the Hebrew and the LXX., neither being exactly followed. The Hebrew has (A.V), "To me belongeth vengeance and recompense;" the LXX., ἐν ἡμέρα ἐκδικήσεως ἀνταποδώσω. And in the same form as in the text the passage is cited Romans 12:19. It may be, in this and some other cases of variation from the LXX., that a text different from ours was used by the New Testament writers. The difference here is quite immaterial with regard to the drift of the quotation.