I always remember Leviticus 17:11, probably for personal reasons. “For the life of the flesh is in the blood, and I have given it for you on the altar to make atonement for your souls, for it is the blood that makes atonement by the life.”
When I was a boy, as my father was building our house, I tried to hand him a hard-wire brush while he was climbing down a ladder. He didn’t see me coming. When he turned his face towards me, the brush bumped into his nose, and one of the fine silver quills stuck into his skin. When he pulled it out, there was a drop of blood the size of a pinhead, a tiny dark purple dome that entered the open air and almost whispered, “No . . . no.” Blood is not meant to go on the outside. It maintains its vitality by being concealed. Blood is meant to be covered.
It is also meant to move. Years later, I stood with my brothers and mother in our living room, watching my father die. The tumor had grown, had taken too much, as cancer always does, and now his respiratory system, the last remaining function of his body, was shutting down. I will never forget the moment when the hospice nurse told us the number of breaths he had left at the end: three. I have never counted down from three that way before, silently, surrounded by those who shared my own blood. After the last air left his lungs, his flesh grew paler. It was the blood stilled, the heart no longer thudding that took the color from his skin. That, I believe, is when his soul made an exit. When blood settles and ceases to flow, the soul must go, for our souls, like tired dogs, seek out the ancient scent of life that resides in the Spirit of God.
Blood, in a sense, carries a burden. It carries life—a divine gift as mysterious as it is requisite. In God’s great providence, it is the only thing that can atone for sin, that can cover a transgression, that can restore the divine-human relationship. For years, this has puzzled me to the core. How can red liquid have the potency to prevail over darkness and death by the burden it bears? Why does blood atone for sin?
I cannot help ruminating. I think the atoning power of blood has something to do with giving up the burden of life, effected by ending the two qualities of blood: its internality and movement. When blood is shed, the inside comes outside, and the movement ceases. Sanctity is uncovered and stilled. The blood can thus no longer bear its burden, the burden of sacred life, which has its ultimate origin in God (cf. John 14:6). So, that life is set free to do the impossible, to do spiritually what God has done physically from the beginning: separate light from darkness (Gen 1:4), separate image-bearing sinners from the evil they have done.
In the mysterious, God-governed process of atonement, we can easily forget that it is not blood in itself that atones, for blood only “makes atonement by the life” (Lev 17:11). It is life that rights a wrong and restores the morally destitute. It is life that breaks the power of sin and death (Rom 6:9–10). That is why we look with hope toward the day when all that is scarred by sin is “swallowed up by life” (2 Cor 5:4). Even more mysterious and glorious is the truth that this life is tri-personal: the Father of the living (Mark 12:27), who gave the Son of life (John 1:4; 14:6), by the life-giving Spirit (John 6:63; Rom 8:10; 1 Cor 15:45)!
In this light, the beauty of Christ’s blood takes on a new aura. Every drop of blood from Christ’s body, every red-lined laceration, every tear in his skin was an instance of holy blood giving up its burden, the burden of life. It is only by that burden that we are re-born. It is only by life that we inherit life. That is why we can say, “Soul works covering for soul.” The life of one soul can vicariously atone for the life of another precisely because blood gives up its burden.
Blood is no little thing. It carries, in the end, the weight of the world, and salvation of every sinner.
 Geerhardus Vos, Biblical Theology: Old and New Testaments (1948; repr., Carlisle, PA: Banner of Truth, 2014), 165.