Sin was ever a bloody business. People are wounded, killed, battered by sin.
“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.” (Lev. 17:11)
The person of Christ is fully God and fully man. God lays down His life on the cross. There is paradox, here. Not a mystery to be solved, a real paradox held in tension. It is not a “human” sacrifice.
“For this reason the Father loves me, because I lay down my life that I may take it up again. No one takes it from me, but I lay it down of my own accord. I have authority to lay it down, and I have authority to take it up again. This charge I have received from my Father.” (John 10:17-18)
Who, but God, can die and rise, again, of his own power?
On the cross, we see a God willing to die for us. We also see all the weight of human sin hurled at Him, heaped on Him – it is a murder. The cross is the anvil of sin and God hammers out justice.
“And if Christ has not been raised, your faith is futile and you are still in your sins. Then those also who have fallen asleep in Christ have perished. If in Christ we have hope in this life only, we are of all people most to be pitied.” (1 Cor. 15:17-19)
God overcomes death. Human sacrifices are merely murders. No one comes back from them.
“For our sake he made him to be sin who knew no sin, so that in him we might become the righteousness of God.” (2 Cor. 5:21)