Why do some people feel that it is necessary to go to a priest to have their sins taken away?

Many people go to a priest because the priest's spiritual authority can be traced back, bishop by bishop, to the twelve apostles of Christ. These men were entrusted by Jesus to spread the message of Christ's gospel and to protect that message from false teaching.

Going to a priest and confessing one's sin is participating in the 'sacrament of reconciliation.' This sacrament, according to orthodox theologians, was established by Jesus Christ after his resurrection. The event can be found in the New Testament book of John 20:22-23.

For many people, there is great comfort in hearing a human voice (especially one that is a direct representative according to scripture) say one's sins are forgiven.