Sacred tradition in Catholicism makes the Sacrament of Penance and Reconciliation the pathway by which life in Christ is possible. In the United States at least, before receiving first communion, children must first go to reconciliation. All Catholics who are conscious of mortal sin, must confess their sins before receiving communion. In fact, the only other way to "have life within you", to a Catholic is to get Baptized, then be hit by a bus (or desire Baptism in some way and be hit by a bus (or to stop someone from being hit by a bus and be hit by a bus *))
In any event, our justification is that Jesus told his disciples to do this:
John 20:21-23 (NIV)
21 Again Jesus said, “Peace be with you! As the Father has sent me, I am sending you.” 22 And with that he breathed on them and said, “Receive the Holy Spirit. 23 If you forgive anyone’s sins, their sins are forgiven; if you do not forgive them, they are not forgiven.”
He didn't tell Mary Magdalene to do this, he didn't tell His Blessed Mother to do this, he didn't tell Pontius Pilate to do this, he didn't tell the Pharisees to do this, he didn't tell Lazarus to do this, he didn't tell Jarius to do this, he didn't even tell John the Baptist to do this.
In one sense, yeah, he's telling us to do this, but in another sense. The sense that the Pharisees knew in Mark 2:7:
Mark 2:7 (NIV)
7 “Why does this fellow talk like that? He’s blaspheming! Who can forgive sins but God alone?”
He's saying, when you forgive sins, they are GONE. That's what a priest tells you in confession. He tells you, that in God's eyes, your sins are no more. You could still be thrown in jail for them, you may still have to pay up in purgatory for them, but whatever you did is forgiven forever. Our sin has eternal significance, so do Christ's words in Matt 16:19
Matthew 16:19 (NIV)
19 I will give you the keys of the kingdom of heaven; whatever you bind on earth will be bound in heaven, and whatever you loose on earth will be loosed in heaven.”
The power that the apostles confer to their successors, the Bishops and their helpers, the priests, has the eternal significance of both bringing down Jesus to be with us in the Holy Sacrament of the Altar and acting In Persona Christi to forgive sins in the confessional.
Also, priests themselves have no inherent right to hear confessions. Priests are given the faculties to do so from the Bishop of the diocese they are stationed in. But there are extraordinary circumstances in case of emergency and also times like World Youth Day when priests from all over the world will congregate when any priest will hear your confession.
But, regardless of the priest, the person making the confession must have Contrition which can come in two forms
- Fear of God's punishment (imperfect contrition)
- Desire to love God and please him (perfect contrition)
If they don't have these things, then they're not truly forgiven, there's no magic involved here. There is only forgiveness and Jesus. The priest sort of recedes into the background here. He's incredibly helpful because he often gives you great advice anonymously and freely. But the forgiveness part, that's all the Holy Spirit.
*buses are not sacramental in nature and have no ecclesiastical significance, I bring them up solely for the visual.