Augustine of Hippo

Now, penance itself is often omitted because of weakness, even when in church custom there is an adequate reason why it should be performed. For shame is the fear of displeasing men, when one loves good opinion more than he regards judgment, which would make him humble in penitence. Thus not only for one to repent but also in order that he may be enabled to do so, the mercy of God is prerequisite. Otherwise, the apostle would not say of some, "In case God gives them repentance."