Catechism of the Council of Trent: "Forgive our trespasses as we forgive those who trespass against us"
Those Unable To Forget Injuries
There are those who, aware that they ought to bury injuries in voluntary oblivion and ought to love those that injure them, desire to do so, and do so as far as they are able, but feel that they cannot efface from their mind all recollection of injuries. For there lurk in the mind some remains of private grudge, in consequence of which such persons are disturbed by misgivings of conscience, fearing that they have not in simplicity and frankness laid aside their enmities and consequently do not obey the command of God.
Here, therefore, the pastor should explain the contrary desires of the flesh and of the spirit; that the former is prone to revenge, the latter ready to pardon; that hence a continual struggle and conflict goes on between them. Wherefore he should point out that although the appetites of corrupt nature are ever opposing and rebelling against reason, we are not on this account to be uneasy regarding salvation, provided the spirit persevere in the duty and disposition of forgiving injuries and of loving our neighbour.
Those Who Do Not Love Their Enemies
There may be some who, because they have not yet been able to bring themselves to forget injuries and to love their enemies, are consequently deterred by the condition contained in this Petition from making use of the Lord's Prayer. To remove from their minds this pernicious error, the pastor should adduce the two following considerations.
(In the first place), whoever belongs to the number of the faithful, offers this prayer in the name of the entire Church, in which there must necessarily be some pious persons who have forgiven their debtors the debts here mentioned.
Secondly, when we ask this favour from God, we also ask for whatever cooperation with the Petition is necessary on our part in order to obtain the object of our prayer. Thus we ask the pardon of our sins and the gift of true repentance; we pray for the grace of inward sorrow; we beg that we may be able to abhor our sins, and confess them truly and piously to the priest. Since, then, it is necessary for us to forgive those who have inflicted on us any loss or injury, when we ask pardon of God we beg of Him at the same time to grant us grace to be reconciled to those against whom we harbour hatred.
Those, therefore, who are troubled by that groundless and perverse fear, that by this prayer they provoke still more the wrath of God, should be undeceived and should be exhorted to make frequent use of a prayer in which they beseech God our Father to grant them the disposition to forgive those who have injured them and to love their enemies.
How to Make this Petition Fruitful
Penitential Dispositions
But that this Petition may be really fruitful we should first seriously reflect that we are suppliants before God, soliciting from Him pardon, which is not granted but to the penitent; and that we should, therefore, be animated by that charity and piety which are fitting in penitents, whom it eminently becomes to keep before their eyes, as it were, their own crimes and enormities and to expiate them with tears.
Avoidance Of Dangers Of Sin
To this thought should be joined caution in guarding for the future against every occasion of sin, and against whatever may expose us to the danger of offending God our Father. With this solicitude the mind of David was occupied when he said: My sin is always before me; and: Every night I will wash my bed; I will water my couch with my tears.
Imitation Of Fervent Penitents
Let each one also call to mind the ardent love of prayer of those who obtained from God through their entreaties the pardon of their sins. Such was the publican, who, standing afar off through shame and grief, and with eyes fixed on the ground, only smote his breast, crying: O God, be merciful to me, a sinner. Such was also the woman, a sinner, who, standing behind Christ the Lord, washed His feet, wiped them with her hair, and kissed them. Lastly, there is the example of Peter, the Prince of the Apostles, who going forth wept bitterly.
Frequent Use Of The Sacraments
They should next consider that the weaker men are, and the more liable to diseases of the soul, which are sins, the more numerous and frequent are the remedies they need. Now the remedies of a sick soul are Penance and the Eucharist; these, therefore, the faithful should frequently make use of.
Almsdeeds
Next almsdeeds, as the Sacred Scriptures declare, are a medicine suited to heal the wounds of the soul. Wherefore, let those who desire to make pious use of this prayer act kindly to the poor according to their means. Of the great efficacy of alms in effacing the stains of sin, the Angel of the Lord in Tobias, holy Raphael, is a witness, who says: Alms deliver from death, and the same is that which purgeth away sins, and maketh to find mercy and life everlasting. Daniel is another witness, who thus admonished King Nabuchodonosor: Redeem thou thy sins with alms, and thy iniquities with works of mercy to the poor.
The Spirit Of Forgiveness
The best alms and the most excellent act of mercy is forgetfulness of injuries, and good will towards those who have injured us or ours, in person, in property, or in character. Whoever, therefore, desires to experience in a special manner the mercy of God, should make an offering to God Himself of all his enmities, remit every offence, and pray for his enemies with the greatest good will, seizing every opportunity of doing them good. But as this subject was explained when we treated of murder, we refer the pastor to that place.
The pastor ought to conclude his explanation of this Petition with this final reflection, that nothing is, or can be conceived, more unjust than that he who is so rigorous towards men as to extend indulgence to no one, should himself demand that God be mild and kind towards him.