Through the sacraments of Christian initiation, man receives the new life of Christ.
How we carry this life "in earthen vessels," and it remains "hidden with Christ in God."
The Sacrament of Reconciliation (or confession) and the Sacrament of Anointing of the Sick are the two sacraments of healing. After someone receives the Sacraments of Initiation they become a new creature in Jesus Christ. Unfortunately, we are still subject to all kinds of temptations which threaten the purity of faith received at Baptism. Should someone succumb to temptation and fall into sin, "The Lord Jesus Christ, physician of our souls and bodies, who forgave the sins of the paralytic and restored him to bodily health, has willed that his Church continue, in the power of the Holy Spirit, his work of healing and salvation" [CCC 1421]. This is accomplished through the Sacrament of Reconciliation!
Is Reconciliation a biblical teaching?
Confessing our sins to a priest was Christ's plan ever since the beginning. Indeed, Jesus himself gave the Apostles the authority to forgive or retain sins. "Jesus said to them again, 'peace be with you. As the Father has sent me, even so I send you.' And when he had said this, he breathed on them, and said to them, 'Receive the Holy Spirit. If you forgive the sins of any, they are forgiven; if you retain the sins of any, they are retained.'" (John 20:21 - 23) What's important to remember when confessing to a priest is that Jesus himself is the one who forgives sins through the priest, who is Jesus' instrument of reconciliation.
There are sound reasons why the Sacrament of Confession is more beneficial to the soul rather than simply speaking to God interiorly. "The confession (disclosure) of sins, even from a simply human point of view, frees us and facilitates our reconciliation with others. Through such an admission man looks squarely at the sins he is guilty of, take responsibility for them, and thereby opens himself again to God and to the communion of the Church in order to make a new future possible." [CCC1455] It is easy to avoid responsibility and justify our actions when we have no accountability. Jesus wisely provided such accountability in this sacrament.
How often should I confess?
We are encouraged to confess our sins regularly, especially grave sins because these cut us off from the love of God and we fall out of a state of grace, which is necessary to enter heaven. "According to the Church's command, 'after having attained the age of discretion, each of the faithful is bound by an obligation faithfully to confess serious sins at least once a year.' Anyone who is aware of having committed a mortal sin must not receive Holy Communion, even if he experiences deep contrition, without having first received sacramental absolution." [CCC 1457] By examining our consciences daily and confessing our sins with contrition and sorrow, we demonstrate gratitude for our Lord's torture and death, and we grow in deeper love of God and neighbor.