Introduction

There are some communities which erroneously claim that giving your confession to a priest is blasphemous. As Catholics we believe that ordained priests of the Church act as instruments through which God can forgive your sins.

Catechism
Only God forgives sins. Since he is the Son of God, Jesus says of himself, "The Son of man has authority on earth to forgive sins" and exercises this divine power: "Your sins are forgiven." Further, by virtue of his divine authority he gives this power to men to exercise in his name."
- Catechism of the Catholic Church, 2nd ed., (1997), n.1441
Confession to a priest is an essential part of the sacrament of Penance: "All mortal sins of which penitents after a diligent self-examination are conscious must be recounted by them in confession, even if they are most secret and have been committed against the last two precepts of the Decalogue; for these sins sometimes wound the soul more grievously and are more dangerous than those which are committed openly."
- Catechism of the Catholic Church, 2nd ed., (1997), n.1456
Scripture

Lev. 5:4-6; Lev. 19:21-22 - Under the Old Covenant, God used priests to forgive and atone for the sins of others.

Mt. 16:19; Mt. 18:18 – Under the New Covenant the apostles are given authority to “bind and loose” penalties of sin.

Jn. 20:21-23 – Under the New Covenant Jesus gave the apostles the power to forgive or retain sins.

Tradition & Fathers
"In church confess your sins, and do not come to your prayer with a guilt conscience. Such is the Way of Life...On the Lord's own day, assemble in common to break bread and offer thanks; but first confess your sins, so that your sacrifice may be pure."
- Didache Apostolorum, 4:1, 14:1 (A.D. ~90)
"… Thine high priest, that he may minister blamelessly by night and day, that he may unceasingly behold and appropriate Thy countenance and offer to Thee the gifts of Thy holy Church. And that by the high priestly Spirit he may have authority to forgive sins..."
- St. Hippolytus of Rome, Apostolic Tradition (A.D. 170-235)
"In addition to these there is also a seventh, albeit hard and laborious: the remission of sins through penance...when he does not shrink from declaring his sin to a priest of the Lord."
- Origen of Alexandria, Homilies on Leviticus (A.D. 184-253)
"All mortal sins are to be submitted to the keys of the Church and all can be forgiven; but recourse to these keys is the only, the necessary, and the certain way to forgiveness. Unless those who are guilty of grievous sin have recourse to the power of the keys, they cannot hope for eternal salvation. Open your lips, them, and confess your sins to the priest. Confession alone is the true gate to Heaven."
- St. Augustine of Hippo, Christian Combat (A.D. 354-430)
"I have recently heard that some have unlawfully presumed to act contrary to a rule of Apostolic origin... All that is necessary, however, is for the sinner to manifest his conscience in a secret confession to the priests alone…It is sufficient, therefore, to have first offered one’s confession to God, and then also to the priest, who acts as an intercessor for the transgressions of the penitents."