In Christendom’s earliest days, people confessed their sins publicly. As you might imagine, this was humiliating for pretty much everyone involved. As time went by, the sacrament became more private; priests would often hold a cloth over their face as they sat to hear the faithful confess their sins. Eventually, the confessional “booth” was born, and this afforded the confessor some degree of anonymity.
“Absolution” means forgiveness, and only a priest can provide it. For faithful Catholics, it can be an enormous weight off their shoulders, but entering the confessional booth and spilling your guts doesn’t automatically mean all’s well. Confession is not a license to go back out and do those things all over again (even among Catholics, there’s the old joke about getting a fresh start each week). There are three things the penitent must do to obtain absolution:
It’s not easy, and it takes some getting used to, but it helps to know that the Confessional Seal is absolute. Canon law forbids the confessor (priest, bishop, etc.) from revealing what he has heard, under pain of excommunication.
Although Scripture advises us that we should confess our sins “one to another,” Catholics believe that however admirable confession of one’s sins may be, it is only through the sacrament of Penance that we can receive absolution, and we base this on the following:
Matthew 9:6; 18:18 (wherein Jesus gave His disciples the power to bind and loose); Mark 2:10; Luke 5:24; John 20:20-23; 2 Corinthians 2:10; 5:18; James 5:15-16; Acts 19:18; 1 Timothy 2:5; 6:12; Leviticus 5:4-6; 19:21-22; 2 Samuel 12:14 (God has forgiven David’s sin, but David must nevertheless pay for it—temporal punishment—by losing his child); Nehemiah 9:2-3; Sirach 4:26; Baruch 1; 1 John 5:16-17.
We therefore find plenty of Scriptural basis for the sacrament. John 20:23, where Jesus said, “Whose sins you shall forgive, they are forgiven them; and whose sins you shall retain, they are retained,” raises an important question: How can the disciples forgive sins unless someone is confessing to them? Note that He does not give this authority to anyone else, just His disciples—the first bishops—and it goes hand in hand with the power of binding and loosing. It is, in fact, useless without it, because the authority to forgive sins could not extend to the hereafter without the power to bind and loose.
The questions remains for many people, including even some Catholics, why not just confess your sins directly to God? It is God, after all, whom our sins offend. Why not just pray and beg His forgiveness? The Church teaches that our sins can in fact be forgiven by appealing directly to God on our own, but the sacrament of Penance ensures that our confession will be properly disposed: it’s part of the priest’s job to ensure that a fitting work of penance be prescribed for the confessor. This will of course vary according to the sin, and only the priest (who does not himself forgive sins, but merely acts on behalf of our Lord) can determine the proper penance. That’s why Jesus established this method.
Now, what did the Fathers teach about the practice of confession? The Didache (which, if not written by the Apostles themselves, was almost certanly written by their disciples, and in any case remains the earliest example outside the Bible of Christian teaching) says “thou shalt confess thy transgressions in the Church.” That certainly seems unequivocal, but it’s a directive. Did the early Christians actually abide by it? According to Irenaeus, in 180 A.D. public confessions were commonplace. And did the Fathers believe that priests had the authority to hear confessions and absolve people of their sin? Hippolytus did. In 215 A.D. he wrote that priests had the authority, given by our Lord, to absolve people of their sins. And in 220 A.D. Tertullian wrote that by papal edict, those who had confessed their sins (specifically adultery and fornication, in that decree) were forgiven.
So we’ve established a Scriptural basis and cleared up any doubt that the early Church Fathers not only believed the sacramental authority to bind and loose, and to hear confessions and forgive sins, extended to duly ordained Church clergy, but that that authority was exercised frequently. Aside from Scripture, then, there is also a very early historical precedent for the sacrament of Confession. It is not, therefore, a “Catholic invention” or innovation of man, as many Protestants and non-Catholics believe.