John 20:23 — whosesoever sins ye remit, they are remitted unto them; and whosesoever sins ye retain, they are retained.
Confession to one another is an aspect of Christian life that seems to get little coverage in Protestant — and especially evangelical — circles. Perhaps it is because of a fear of association with the Catholic sacrament. If so, the fear is misplaced, and a vital resource is being neglected.
John 20:23 should play a key part in understanding the place of confession in our lives. It is important to understand that Jesus was not just addressing the apostles in that room. He was addressing a group of disciples. By proxy, He was chartering the whole church — every member — not a limited group. Note that He was not granting the ability to forgive sins but, as we find in Barnes’ Notes:

To establish in all the churches the terms and conditions on which men might be pardoned, with a promise that God would confirm all that they taught; that all might have assurance of forgiveness who would comply with those terms; and that those who did not comply should not be forgiven, but that their sins should be retained.

We should understand that this is very different from a special group — priests — having the ability to grant and deny forgiveness!
We should not fear to confess one to another. More, we are instructed to do so: “Confess your faults one to another, and pray one for another, that ye may be healed. The effectual fervent prayer of a righteous man availeth much.” (James 5:16). We are to confess to each other, and pray for each other. None of us is above sin, nor is anyone of us above the need for strengthening from the prayers of others. It is interesting that in talking of sickness James uses two words. The first — “kakopathei” suggests suffering from hardship and troubles (it is sometimes used of the rigors of military service). The second — “asthenei” implies feebleness, tiredness — from which we may all suffer. Confession, in sharing the burden of sin, can ease the burden and give us strength. The Bible tells us that it can have many other benefits.

Personally, I have found confession to be essential. Even before I was saved I found it hard to maintain a denial of guilt. Since I was saved I have found that I must confess — most particularly when I have offended a particular individual. Jesus’s words in Matthew 5:23-26 weigh heavily on me. I must confess.