Christ died for the forgiveness of sin.

Christ consecrated His death for the forgiveness of sin at His final Passover. "This is the cup of My Blood; the Blood of the New and Eternal Covenant. It will be shed for you and for all for the forgiveness of sin."

Christ gave the power to forgive or retain sin to His Apostles after breathing the Holy Spirit upon them. "Whose sins you forgive, they will be forgiven; whose sins you retain, they will be retained." We are to confess our sins, one to the other.

http://transporter.com/apologia/confession.html