For we know Him that hath said, Vengeance belongeth unto me, I will recompense, saith the Lord. And again, The Lord shall judge His people (Hebrews 10:30).
In the verses preceding our text, the writer of Hebrews explains how the work of Christ replaces the works of the law once and for all time. As a result, believers have access to God through the shed blood of Christ (v.19) who also serves as our high priest (v.21). However, if we sin willfully after we know the truth, then there is no more or other sacrifice possible, and we can expect serious judgment (v.27). There is great risk in rejecting the blood of the covenant (v.29).
Now, what about the two quotes which the writer cites in our text? They appear to come from Deuteronomy 32:35,36: To me belongeth vengeance, and recompense; their foot shall slide in due time: for the day of their calamity is at hand, and the things that shall come upon them make haste. For the LORD shall judge His people, and repent Himself for His servants, when He seeth that their power is gone, and there is none shut up, or left.
These verses are part of a song that Moses sang to extol the virtues of God. In the midst of the lyrics Moses relates the behavior of Jeshurun (Israel), whose prosperity had turned the nations head away from God (v.15), the one who had made him; he lightly esteemed the rock of his salvation. At this time, Moses is about to transfer the leadership over to Joshua, and then die, before the Israelites enter Canaan. He clearly points the people to what their God will do for them, in or out of His grace and mercy. Rejoice, O ye nations, with His people: for He will avenge the blood of His servants . . . and will be merciful . . . to His people (Deuteronomy 32:43). Blessing or vengeance: Which will it be? KBC