There is only one great truth that was made available to redeem man from the problem of sin, since Creation and that has been blood. From the Garden of Eden to the Garden of Gethsemane were the Lamb of God even sweated blood drops to the Cross of Calvary were His side was pierced and blood ran red. It was clear that His blood paid it all.
In the first three chapters of Romans, Paul makes the argument that everyone, Jew and Gentile alike, is under the condemnation of God and deserving of His wrath (Romans 1:18). Everyone has sinned and fallen short of the glory of God Romans 3:23. All of us deserve His wrath and punishment. God in His infinite grace and mercy has provided a way that His wrath can be appeased and we can be reconciled to Him. That way is through the sacrificial death of His Son, Jesus Christ, as the payment for sins. It is through faith in Jesus Christ as God’s perfect sacrifice that we can be reconciled to God. It is only because of Christ’s death on the cross and His resurrection on the third day that a lost sinner deserving of hell can be reconciled to a holy God. The wonderful truth of the gospel is that Christians are saved from God’s wrath and reconciled to God not because “we loved God, but that He loved us and sent His Son to be the propitiation for our sins” 1 John 4:10
The New Testament epistle to the Hebrews builds the bridge from the Old Testament sacrificial system (and its blood) to the new covenant and Jesus’s once-for-all sacrifice (Hebrews 9:7, 12). Throughout the Bible, blood represents life (for instance, Genesis 9:4), and the spilling or shedding of blood, in turn, depicts death Leviticus 17:11, 14; Deuteronomy 12:23. Because the just penalty of human sin against God is death Romans 6:23, the death of sanctioned animal sacrifices, through the presentation of their blood, stood in temporarily for the requirement of death for sinners. Yet the high priest had to return year after year, “repeatedly” Hebrews 9:7; 9:25, because “it is impossible for the blood of bulls and goats to take away sins” (Hebrews 10:4). The repeated animal sacrifices were delaying the inevitable, waiting on God’s fullness of times. One day a final reckoning for sin must come.
Christians, of course, believe and celebrate that now in Christ, and under the terms of a new covenant, the reckoning has come. Jesus willingly “offered himself” Hebrews 9:14 by “once for all” shedding “his own blood” (Hebrews 9:12), bringing to its intended completion the temporary covenant that came before (the old covenant) and inaugurating in its place an “eternal covenant,” Hebrews 13:30 which we call the new covenant.
Hebrews celebrates some of the specific benefits Christians enjoy because of Jesus’s blood (Hebrews 10:19; 13:12), but it’s the apostle Paul, in particular, who celebrates the manifold grace that comes to us because of his blood. In one sense, we can connect to Jesus’s blood every divine grace that comes to us, but five times Paul makes the connection explicit, with both the mention of blood and a specific aspect of what Christ has secured for us with his death.