If by “confession” you mean acknowledgement of wrongdoing and seeking of forgiveness, other religions do have confession. In Judaism, for example, it’s called Teshuva or “repentance”, apology, return, going back to who you are meant to be. Teshuva is the gesture of returning to God, of letting go of your arrogance, your waywardness, your sinfulness and going back to your ultimate Source. It represents the possibility that even the most degenerate sinner can be reunited with God. Teshuvah is the dominant theme during the ten days between Rosh Hashanah (the Jewish New Year, a day of awakening) and Yom Kippur (the day of Atonement and asking forgiveness) in the early Fall.
I was talking with a Muslim teacher last week, and he, too, was sharing how, when a Muslim sins, there must be an acknowledgement of wrongdoing, a spirit of repentance, and the person must ask God for forgiveness and trust that it is given. Repentance for sin is part of what Muslims are expressing during their month-long fast of Ramadan.
What you don’t find, however, is a “middleman” such as the priest-confessor in the sacrament of reconciliation. Why does Catholicism offer this? Because it’s an incarnational faith. Given the defining event we celebrate at Christmas–the Incarnation/enfleshment of God–the enfleshment of grace is a profound theme that emanates throughout all of Catholic spirituality and finds concrete expression in the sacraments. We are initiated into the divine life through baptism/water. We are strengthened in our faith in confirmation as oil is rubbed upon our heads. We draw closer to God week by week through the consecrated bread and wine of holy communion.
And similarly, when we confess our sins, God wants us to know that our offenses are forgiven by letting our ears actually hear the words for which our hearts long: “I absolve you from all your sins, in the name of the Father, and of the Son, and of the Holy Spirit. Go in peace.”
The incarnation of God in a historical person who gave his life to set us free from our sins is an article of faith that is unique to Christians. Jesus is our mediator. The presence of a “middle-man”, a mediator, in the Catholic way of seeking forgiveness of sin, therefore, is totally consistent with our conviction of faith that God’s grace to us is mediated in visual, audible, palpable ways.