Sometimes, those of us rasied in western catholicism and its descendant protestant or evangelical churches can get the idea that we seek forgiveness of sin because otherwise we are in legal trouble with the Big G. According to this way of thinking, we need to acknowledge our miserable failures and our petty failures which happen to everyone, humiliate ourselves and beg for mercy because otherwise we will go to hell in a handbasket. While there's a lot of truth to this, the eastern, orthoodox perspective is more that sin (offenses against God's law or reality) are something we can't avoid by our own strength but really, really toxic to how our body and soul work. In other words, sin makes us spiritually sick. It injures our ability to live in God's power and character; it reduces us to depending on our own strength (which isn't enough) and catches us like mice on a sticky trap in compulsive, addictive, destructive behavior and completely separates us from life-giving relationship with God. Unforgiven sin makes it impossible to benefit from everything Christ did for us.
What did Christ do for us, anyway? He forgave our sins and gave us eternal life--a participation in His own Holy Spirit--divine energies. This life lasts forever--heaven--except when we return to sin--and find ourselves caught in compulsion, cut off from the supernatural life of the Holy Spirit, all God's gifts and marvelous ways of acting in our soul. The Joy of His Presence. The power of prayer. Gone! We're just left with our smart attitude and sense of right and wrong--but no power to actually accomplish much.
And so we seek the incredible gift of the forgiveness of sins! Just as having a refrigerator full of food does no good if we don't pick up a fork and bring the food to our mouth, Christ's willingness to forgive us does no good unless we confess, repent (decide to try not to do it), and ask for forgiveness. But, God, being God, is so gracious. He doesn't just give us, with forgiveness of sins, what we lost, He rewards our seeking Him. He fills us more richly with His Holy Spirit.
As we grow in the spiritual life, we learn that even very little sins have tremendous power over us. Refusal to forgive hurts us and allows demons to tempt us with rejecting others and cause us problems. Judging others and having an attitude of superiority is a barrier to God answering our prayers. Something that small can cut our lives, families, work, ministry off from God's power. Do you remember how the saints always seem to be the ones working miracles? It's because of their purity--the amount of God's forgiveness they have received! They trust God with their lives. They are ready to give up every thing--no matter how slight --that keeps them from God. And God gives them something more for every little sin they turn from. His Word is true! He always has more for us!
So mother church invites us, in Lent, to examine our consciences by the Light of God's commandments (a good examination of conscience available anywhere) and to allow the Holy Spirit to examine our conscience. How do we get that? We ask in prayer that God show us any sin in our lives! And He answers that prayer!
And then we are invited to receive God's mercy and rich outpouring of graces! We can confess our sins in prayer, of course, and God will forgive us. That is a doctrine of every Christian church--including the Roman Catholic Church. But what the Bible tells us--if we are really willing to obey God in all things--is that we are to confess our sins "to one another", to the presbyter, which in English is priest. Why does the Scripture say this? The passage goes on, "Confess your sins to one another so that you may be healed." Be healed of what you ask? Perhaps shame, perhaps weakness, perhaps disconnect from God and the community? Perhaps wounds of sin that leave us with less than a sense of wellbeing and joy or even psychological illness? Or physical illness! Some poeple have been healed in the Confessional. I remember listening to two seminars on healing the wound of abortion trauma; one was taught by a protestant and the other by a Catholic. But both women agreed: the wound of abortion--a really deep wound psychologically harming wound like that--never heals without confession before another person! But whether we go that extra step of auricular Confession--with all its amazing graces, or we just ask the Lord's forgiveness in our closet, the important thing is that we take a step closer to God--a step of reaching out and receiving what He has for us.