Hebrews 10:30 - Matthew Poole's English Annotations on the Holy Bible

For we know him that hath said: For brings in the proof of the soreness of God's punishment to be inflicted on apostates, from God's own testimony about it; which we, who are conversant with the Scriptures, are well acquainted with; we know what God hath spoken, and by whom he hath spoken it, 1 Thessalonians 9:29. Their knowledge of it was clear and certain, it being spoken to them by Moses, and written for them, Deuteronomy 32:35,36. Vengeance belongeth unto me, I will recompense; to me is vengeance and recompence; which are the words of the Hebrew text. To me, the sovereign Being, the supreme and universal Lawgiver and Judge, doth belong the universal right and power of vindictive justice. It is his propriety, as he will avenge all injuries against his people, he will much more avenge the sins and injuries against his Son; and will actually return to evil-doers, as a recompence for their sins, the evil of punishment. He is not only just and powerful, but actually manifesting both in his retribution on them, Deuteronomy 32:41,43 Psa 94:1 Romans 12:19 2 Thessalonians 1:8. Saith the Lord; Jehovah saith it, who is faithful and true, powerful, and constant to his threatenings, as well as his promises. This he saith to, and threatens apostate Jeshurun with, who revolted from God, and served idols, Deuteronomy 32:15-17. And again, The Lord shall judge his people: a further testimony is urged from God's vindication of his people, when he hath punished apostates, taken from Deuteronomy 32:6, and Psalms 135:14. The sovereign Being of righteousness, the same Jehovah as before, will rule, justify, save, deliver, and vindicate his covenant people from the contempt and vilifying of his Son and them, by punishing severely such who, by their apostacy from him and them, are guilty of it. He will certainly take vengeance on them, and thereby clear the innocency, truth, and goodness of his, who are trampled on by them.