Rick Phillips, in his commentary on Hebrews, gives a wonderful description of the doctrine of the atonement and its importance in our lives:
The atonement is a repulsive subject to many; they flinch to think that God would require blood-shedding in order to achieve his goals. There is hardly a more arresting sight than that of human blood being spilled. People see blood and they faint. They stumble upon a crime scene, perhaps, or a traffic accident, and stop dead in their tracks to realize they are looking at a stain of human blood upon the ground. Blood is the very presence of death and suffering and lament. Yet it is with the shedding of his own Son’s precious blood that God makes his most important and essential and final statements to this world, statements we must hear and receive if we are to come to God for salvation.
The first statement that the blood of Christ makes is God’s holy judgement on our sin. It is only, really, when we see the blood of the Son of God spilled upon the earth that we comprehend anything of the sinfulness of sin. The Puritan Jeremiah Burroughs wrote: “From hence we see what is the evil of sin. How great it is that has made such a breach between God and my soul that only such a way and such a means must take away my sin. I must either have lain under the burden of my sin eternally, or Jesus Christ, who is God and man, must suffer so much for it.” J.C. Ryle adds, “Terribly black must that guilt be for which nothing but the blood of the Son of God could make satisfaction. Heavy must that weight of human sin be which made Jesus groan and sweat drops of blood and agony at Gethsemane and cry at Golgotha, ‘My God, My God, why hast Thou forsaken Me? (Matt. 27:46).”
Second, the blood of Christ also shows the great magnitude of God’s love for us. It is in dimensions appropriate to a cross that Paul speaks of God’s love in Ephesians 3:18, praising its width and length and height and depth.
Third, the blood of Christ proclaims God’s full involvement in our world, at every level… In light of the cross of Christ, the accusation that God is far off and aloof from the reality of this world is in fact the greatest of all blasphemies. For the cross displays God’s involvement in this world in a way that is not only far greater than we could demand, but is far more gracious than we could imagine.
Solid Joys and Lasting Treasures 