88 The same result follows from the opinions of those who assert that little importance should be given to the frequent confession of venial sins. Far more important, they say, is that general confession which the Spouse of Christ, surrounded by her children in the Lord, makes each day by the mouth of the priest as he approaches the altar of God. As you well know, Venerable Brethren, it is true that venial sins may be expiated in many ways which are to be highly commended. But to ensure more rapid progress day by day in the path of virtue, We will that the pious practice of frequent confession, which was introduced into the Church by the inspiration of the Holy spirit, should be earnestly advocated. By it genuine self-knowledge is increased, Christian humility grows, bad habits are corrected, spiritual neglect and tepidity are resisted, the conscience is purified, the will strengthened, a salutary self-control is attained, and grace is increased in virtue of the Sacrament itself. Let those, therefore, among the younger clergy who make light of or lessen esteem for frequent confession realize that what they are doing is alien to the Spirit of Christ and disastrous for the Mystical Body of our Savior.
Source: Mystici Corporis Christi (Vatican.va)