The Enchiridion 82
82 The Mercy of God is Necessary to True Repentance PL 40, 271
Now even penance itself, when by the law of the Church there is sufficient reason for its being gone through, is frequently evaded through infirmity; for shame is the fear of losing pleasure when the good opinion of men gives more pleasure than the righteousness which leads a man to humble himself in penitence. Wherefore the mercy of God is necessary not only when a man repents, but even to lead him to repent. How else explain what the apostle says of certain persons: “if God peradventure will give them repentance”? And before Peter wept bitterly, we are told by the evangelist, “The Lord turned, and looked upon him.”
Poenitentia Dei donum. Nam et ipsa poenitentia, quando digna causa est secundum morem Ecclesiae cur agatur, plerumque infirmitate non agitur; quia et pudor timor est displicendi, dum plus delectat hominum existimatio, quam justitia qua se quisque humiliat poenitendo. Unde non solum cum agitur poenitentia, verum etiam ut agatur, Dei misericordia necessaria est. Alioquin non diceret Apostolus de quibusdam: Ne forte det illis Deus poenitentiam . Et ut Petrus amare fleret, praemisit evangelista, et ait: Respexit eum Dominus .