In order to understand better the theology behind the sacrament, we should look also at the history of the sacrament.
“During the first five centuries of the Christian era, Syriac and Byzantine Christianity would have come to possess the apostolic canons and constitutions, as well as the canons of the Councils of Nicea and Constantinople, and of the Synods of Neocaesarea, Gangre, Laodicea, and Antioch… Later the discipline of penance would become quite varied, eventually declining and even falling prey to abuses among the Jacobites and Nestorians.” (Chapungco, p. 105)
“East and West began to diverge as the West began to include more and more acts in its catalogue of offenses that required the intervention of the Church’s authorities. For its part, the East left it more and more to spiritual directors and holy people to help to heal the sinfulness of those who had recourse to them. The great theologian and bishop Saint Symeon of Thessalonica (died 1022) went so far as to remove the hearing of confessions from the work of the clergy and entrusted it exclusively to the ministry of the monastics—lay monastics at that! This divergence points to two very different attitudes between the two Churches. …
“The east tends to use a medical model for the sacrament. That is, a spiritual guide discerns spirits, the way a physician would examine symptoms, and prescribes remedies for the spiritual illness if needed. Generally in the East the ministry of reconciliation is entrusted to those who prove themselves skilled at it. Priestly ordination alone does not necessarily qualify one to perform this ministry in some Easter Churches. [comment: the same is true in the West]
… “When penance was no longer a lengthy public matter, the Western Church took the concept [of indulgences] and applied it to the residual punishment due to sin that an individual might face after death. The Byzantine Church simply discarded references to indulgences in its penitential practices.” (Appleyard, pp. 22-23)
It is interesting to point out that, in Russia:
“At diocesan conferences after the first [Russian] revolution of 1905, in several places the clergy resolved ‘to abolish private confession and replace it with general confession…. This amounts to abolishing the Orthodox Faith, since without confession the attitude toward religions life as a constant inner struggle is lost, and it is precisely this which distinguishes our faith from the Lutheran and Stundist heresies [Stundists were the forerunners of the Russian Baptists].” (Confession, p. 13)