6 God is loving to man, and loving in no small measure. For say not, I have committed fornication and adultery: I have done dreadful things, and not once only, but often: will He forgive? Will He grant pardon? Hear what the Psalmist says: How great is the multitude of Your goodness, O Lord! Your accumulated offenses surpass not the multitude of God's mercies: your wounds surpass not the great Physician's skill. Only give yourself up in faith: tell the Physician your ailment: say thou also, like David: I said, I will confess me my sin unto the Lord: and the same shall be done in your case, which he says immediately: And you forgave the wickedness of my heart.
Source: Catechetical Lectures (New Advent)