"Forgive us our debts as we also forgive our debtors"
The Lord demands that we ourselves forgive the debts of our debtors just as we, too, ask that our own be forgiven (Mt 6,12). We should know that we cannot receive what we ask with regard to our own sins unless we do the same for those who have sinned against us. And so Christ says elsewhere: “The measure with which you measure will be measured out to you,” (Mt 7,2). And the servant who, having been freed from all his debt, was unwilling to forgive that of his fellow servant was thrown into prison. Because he would not spare his fellow, he lost that for which his master had spared him. Christ establishes this even more forcibly in his precepts when he decrees that...: “When you stand to pray, forgive anyone against whom you have a grievance, so that your heavenly Father may in turn forgive you your transgressions. But if you do not forgive, neither will your heavenly Father forgive your transgressions,” (Mk 11,25-26).
When Abel and Cain first of all offered sacrifice, God did not look at their offerings but at their hearts (Gn 4,3f.). The one whose offering was pleasing to him was the one whose heart was pleasing to him. Abel, the peaceful and just one, by making his offering to God in innocence, taught others to come forward in the fear of God to offer their gift at the altar, with a simple heart, a sense of justice, harmony and peace. By offering sacrifice to God with such dispositions as these he merited to become a precious offering himself and to be the first to offer the witness of martyrdom. By the glory of his blood he prefigured the Lord's Passion because he possessed the Lord's righteousness and peace. Men like these are they who are crowned by the Lord and who will obtain justice along with him on the day of judgement.