Under the old covenant a transfer of identity was made between the one who offered the sacrifice and the sacrifice itself.
Sacrifice in Ancient Israel
The sinner brought "his sin" to the altar to be consumed and also identified with the destruction of the life force of sin - the flesh with its blood.
Leviticus 17:11 For the life of the flesh is in the blood: and I have given it to you upon the altar to make an atonement for your souls: for it is the blood that maketh an atonement for the soul.
I believe this is the parallel Paul is drawing in 2 Corinthians 5:21.
Every animal sacrifice includes special treatment of the animal’s blood, which various biblical passages identity with the life force of the animal (see, for example, Gen 9:4, Deut 12:23). Despite the clear importance of this ritual use of blood, only one verse in the entire Hebrew Bible appears to explain its significance (Lev 17:11). This debated but crucial verse concerns life, not death; animal life on the altar preserves and enhances human life.
Sacrifice in Ancient Israel
The sinner brought "his sin" to the altar to be consumed and also identified with the destruction of the life force of sin - the flesh with its blood.
Leviticus 17:11 For the life of the flesh is in the blood: and I have given it to you upon the altar to make an atonement for your souls: for it is the blood that maketh an atonement for the soul.
I believe this is the parallel Paul is drawing in 2 Corinthians 5:21.