Answer
The author of the book of Hebrews carefully detailed the superiority of the New Covenant over the Old. In Hebrews 10:29, the higher consequence of disregarding the New Covenant is emphasized: “How much more severely do you think someone deserves to be punished who has trampled the Son of God underfoot, who has treated as an unholy thing the blood of the covenant that sanctified them, and who has insulted the Spirit of grace?” This verse builds upon the preceding one, reminding Christians of the judgment the Jews faced for intentional rebellion against the Law of Moses. If the New Covenant is greater than the Old, then those who “trample the Son of God underfoot” and “treat as an unholy thing the blood of the covenant” will face greater judgment. Here, “the blood of the covenant” refers to the blood of Jesus shed on the cross. Trivializing that sacrifice is deemed equivalent to insulting the Holy Spirit and rejecting the Son.
The phrase blood of the covenant originates from an Old Testament text, namely, Exodus 24:7–8: “Then he took the Book of the Covenant and read it to the people. They responded, ‘We will do everything the Lord has said; we will obey.’ Moses then took the blood, sprinkled it on the people and said, ‘This is the blood of the covenant that the Lord has made with you in accordance with all these words.’”
In the Old Testament, the blood of the covenant came from animals, symbolizing the sacrificial element of the Old Covenant. It served as a foreshadowing of the New Covenant, as explained in Hebrews 9:18–22:
This is why even the first covenant was not put into effect without blood. When Moses had proclaimed every command of the law to all the people, he took the blood of calves, together with water, scarlet wool and branches of hyssop, and sprinkled the scroll and all the people. He said, “This is the blood of the covenant, which God has commanded you to keep.” In the same way, he sprinkled with the blood both the tabernacle and everything used in its ceremonies. In fact, the law requires that nearly everything be cleansed with blood, and without the shedding of blood, there is no forgiveness.
Certainly, Christ’s blood, which ratified the New Covenant, surpasses the animal blood of the Old Covenant. Animal blood cannot wash away sin (Hebrews 10:1–4) but is only valuable for ritual purity. The sin of both Old Testament saints and New Testament believers is atoned for through Christ’s blood. For persecuted Jewish Christians tempted to revert to the Old Testament system, the epistle of Hebrews serves as an apologetic for the New Covenant, sealed by the precious blood of Christ.How can one treat this blood of covenant as “unholy”? Rejection of the gospel signifies a disregard for Christ and His sacrifice. The especial warning of Hebrews 10:29 is directed at Jewish individuals who heard and understood the gospel and may even have made a profession of faith, but who were on the verge of turning away from Christ. They were tempted to leave Christ and return to the Old Covenant. To do so would be to insult the Spirit of grace and treat the blood of the covenant as common (verse 29). Such would-be apostates are warned that, if they reject Christ’s sacrifice, “no sacrifice for sins is left” (verse 26).
