Roman Catechism 39.32

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

Section 32. "As we Forgive our Debtors" — The word as may be understood in two senses. It may be taken as having the force of a comparison, meaning that we beg of God to pardon us our sins, just as we pardon the wrongs and contumelies which we receive from those by whom we have been injured. It may also be understood as denoting a condition, and in this sense Christ the Lord interprets that formula. If, He says, you forgive men their offences, your heavenly Father will also forgive you your offences; but if you will not forgive men, neither will your Father forgive you your sins.