Penance, as a mystery of the Orthodox Christian Church, is the reconciliation by Penitents of their sin and alienation from God.
When an Orthodox Christian finds oneself severed by sin from God and the life of the Church, it is through penance that the person returns to communion with God by changing ones ways (metanoia) and repenting ones sins. Within the life in the Church, the Church provides for our formal act of reconciliation with God through the sacrament of penance to allow for the repentance and reconversion of Christians who have fallen away from the life of faith.
There are three main elements to the act of formal penance. First, a sincere sorrow for sins and breaking of communion with God. Second is an open and heartfelt confession of sins. Third is the formal prayer of absolution through which the forgiveness of God through Christ is sacramentally bestowed upon the repentant sinner.
The Orthodox Church adheres strictly to the teaching of the Scriptures that only God can forgive sins, that he does so through Christ in the Church, that his conditions are genuine repentance and the promise of change which are witnessed by confession, and that confession, by definition, is the open and public acknowledgment of sin before God and all mankind.