Why do we have a Confession of Sin?

If we have been redeemed by God through the sacrifice of Christ, we know that all our past, present, and future sins have been atoned and forgiven.

The purpose of confessing our sin corporately is not to despairingly dwell on our sin, but to humble ourselves before the Lord and each other and increase our awareness of our constant need of a savior.  

By confessing our sin, we declare the holiness of God and the sinfulness of man and thereby magnify our worship of the one and only God who can, and does, take away our sins.  We are also immediately reminded and assured of the grace and mercy of God and the forgiveness of sin found only in Christ.