Roman Catechism 39.9

Chapter 39 — Part IV: Prayer — The Fifth Petition: Forgive Us Our Trespasses as We Forgive Those Who Trespass Against Us

Section 9. Christ the Lord, who spoke by the mouth of all these, confirms their teaching by this Petition in which He commands us to confess our sins. The Council of Milevi forbids us to interpret it otherwise. It hath pleased the Council, that whosoever will have it that these words of the Lord's prayer, "forgive us our debts," are said by holy men in humility, not in truth, let him be anathema. For who can endure a person praying, and lying not to men, but to the Lord Himself, saying with the lips that he desires to be forgiven, but with the heart, that he has no debts to be forgiven ?