Confession is a Sacrament for Catholics. This Sacrament is based on Jesus’ teaching in the Bible. It is instituted personally by our Lord Jesus. In **John 20:23 **Jesus said “Whose sins you forgive are forgiven them and whose sins you retain are retained."
Priests are representatives of Jesus on earth, their authority were passed down from the apostles. When we make our confession, the priest it Persona Christi, we actually confess to Jesus. With the authority from our Lord, the priest can absolve our sins, just like what Jesus said in John 20:23 – whose sins you forgive are forgiven. In order for the priest to forgive sins, he has to know the person’s sins first, in order to know, he has to hear, in order to hear, the sins have to be confessed, to be said out.
We definitely can directly pray to God and get forgiveness. However, the Sacrament of Confession is a Sacrament of mercy. It helps to hold ourselves accountable when we concretely articulate our fault to another person. It also gives us a chance to practice humility, receive additional grace in order to avoid sin. Not only from the psychological point of view it helps to hear the words “I absolve all your sins”, the priest also gives advices to help the person avoid sin in the future. One attains a certainty of forgiveness, also receives healing. It is a Sacrament of mercy. We run to mercy, we don’t run away from mercy. There are lots of God’s grace in confession.
But the bottom line is it is personally instituted by our Lord, so we follow his teaching.