Not only did God demonstrate his love for us while we were powerless and held captive to sin, by sending Jesus, he made sure that this act of redemption was a one time victory. Not only are we justified through faith in Jesus' blood, but we are also saved from God's wrath by his blood. No longer are we enemies of God, instead we are His friends. We are fully justified, as if we had never sinned, by faith in his blood.
The first question that naturally arises, is why was Jesus' blood necessary? As you read the Old Testament especially in the Law books, you will see that every sin and transgression had a corresponding sacrifice to it. Hebrews 9:22 adds clarity to this when it says, "...the law requires that nearly everything be cleansed with blood, and without the shedding of blood there is no forgiveness." so a blood sacrifice was necessary to absolved sin and to receive forgiveness from God.
The blotting out of sin was accomplished through the shedding of blood. However Hebrews 10 reminds us, that if sacrifices of animals could made perfect the worshipper, would they not stop being offered? But as it stands, guilt remained upon the person because the blood of bulls and goats were never able to take away sin ( Hebrews 10:1-3 ). However, the Israelites continued to offer sacrifices year after year because guilt remained. And if guilt remains in a relationship then something is not right. However when Jesus came, his blood was able to completely clear the consciousness of sin upon the born again spirit. "How much more, then, will the blood of Christ, who through the eternal Spirit offered himself unblemished to God, cleanse our consciences from acts that lead to death, so that we may serve the living God!" ( Hebrew 9:14 )
So the sacrifice of blood accomplished two things. First, it satisfied God's righteous wrath against sin and corruption. And secondly it was able to remove the traces of sin upon our conscience. We, no longer are held under sins dominion, subject to it's guilt and shame. In fact Colossians 1: 21-22 says, "Once you were alienated from God and were enemies in your minds because of your evil behavior. But now he has reconciled you by Christ's physical body through death to present you holy in his sight, without blemish and free from accusation." In other words, if Christ has presented you to God holy and blameless, then that is what you are. Through faith in Jesus, you are holy, pleasing and acceptable unto God.
"Since we have now been justified by his blood, how much more shall we be saved from God's wrath through him! For if, when we were God's enemies, we were reconciled to him through the death of his Son, how much more, having been reconciled, shall we be saved through his life! Not only is this so, but we also rejoice in God through our Lord Jesus Christ, through whom we have now received reconciliation." ( Romans 5:9-11 ) If when we were God's enemy, he sent Jesus to the cross to die a criminals death in our stead, what wouldn't he do for you now that you have receive right standing with him through faith in Jesus' blood? Jesus atonement for your sin had such a profound effect upon your born again spirit that when God looks at you he sees Jesus. That is cause for rejoicing today!