Pope St. Gregory the Great, in his Dialogues, has an interesting meditation on the necessity to pardon others to obtain forgiveness. What can we learn from the Popes, Saints and Doctors of the Church who, like Our Lord, stress the importance of forgiving our neighbor the every day sins we may all commit against each other?"Chapter Sixty: that we ought to pardon other men their sins, that we may obtain remission of our own.
We have also further to know, that he doth rightly and in good sort demand pardon for his own sin, who doth forgive that which hath been done against himself. For our gift is not received, if, before, we free not our soul from all discord and lack of charity: for our Saviour saith: If thou offer thy gift at the altar, and there thou remember that thy brother hath aught against thee, leave there thy offering before the altar, and go first to be reconciled to thy brother, and then coming thou shalt offer thy gift. (Mat 5:23-24) Wherein we have to consider, that whereas all sin by a gift is loosed, how grievous the sin of discord is, for which no gift is received: and therefore we ought, in soul and desire, to go unto our neighbour though he be far off, and many miles distant from us, and there to humble ourselves before him, and to pacify him by humility and hearty good will, to the end that our Creator, beholding the desire of our mind, may forgive us our own sin, who receiveth a gift for sin. And our Saviour himself teacheth us, how that servant, which did owe ten thousand talents, by penance obtained of his Lord the forgiveness of that debt: but yet because he would not forgive his fellow-servant an hundred pence, which were due to him, that was again exacted at his hands, which before was pardoned. (Matt. 18. 27.) Out of which sayings we learn, that if we do not from our heart forgive that which is committed against us, how that is again required at our hands, whereof before we were glad that by penance we had obtained pardon and remission.
Wherefore, whiles time is given us, whiles our judge doth bear with us, whiles he that examineth our sins doth expect our conversion and amendment: let us mollify with tears the hardness of our heart, and with sincere charity, love our neighbours: and then dare I speak it boldly, that we shall not have any need of the holy sacrifice after our death: if, before death, we offer up ourselves for a sacrifice unto almighty God." http://www.tertullian.org/fathers/gregory_04_dialogues_book4.htm#C60
Pope St. Gregory the Great, "to speak it boldly" almost seems to promise us, that if we habitually live forgiving all who offend us, especially as the Lord commands before offering Sacrifice at Mass, we will almost not need that Sacrifice to be offered for us after death! That is, Pope St. Gregory the Great says that those who are accustomed to forgive completely, can hope to go to Heaven without Purgatory. What is the best way we can each try to practice forgiveness in our day to day life?