From Pope St. John Paul II’s Apostolic Exhortation Reconciliatio et Pænitentia (1984):
The truths mentioned above, powerfully and clearly confirmed by the synod and contained in the propositions, can be summarized in the following convictions of faith, to which are connected all the other affirmations of the Catholic doctrine on the sacrament of penance.
The first conviction is that for a Christian the sacrament of penance is the primary way of obtaining forgiveness and the remission of serious sin committed after baptism. Certainly the Savior and his salvific action are not so bound to a sacramental sign as to be unable in any period or area of the history of salvation to work outside and above the sacraments. But in the school of faith we learn that the same Savior desired and provided that the simple and precious sacraments of faith would ordinarily be the effective means through which his redemptive power passes and operates. It would therefore be foolish, as well as presumptuous, to wish arbitrarily to disregard the means of grace and salvation which the Lord has provided and, in the specific case, to claim to receive forgiveness while doing without the sacrament which was instituted by Christ precisely for forgiveness. The renewal of the rites carried out after the council does not sanction any illusion or alteration in this direction. According to the church’s intention, it was and is meant to stir up in each one of us a new impulse toward the renewal of our interior attitude; toward a deeper understanding of the nature of the sacrament of penance; toward a reception of the sacrament which is more filled with faith, not anxious but trusting; toward a more frequent celebration of the sacrament which is seen to be completely filled with the Lord’s merciful love.
— Reconciliatio et Pænitentia 31