38 The sevenfold number of these petitions also seems to me to correspond to that sevenfold number out of which the whole sermon before us has had its rise. For if it is the fear of God through which the poor in spirit are blessed, inasmuch as theirs is the kingdom of heaven; let us ask that the name of God may be hallowed among men through that “fear which is clean, enduring for ever.” If it is piety through which the meek are blessed, inasmuch as they shall inherit the earth; let us ask that His kingdom may come, whether it be over ourselves, that we may become meek, and not resist Him, or whether it be from heaven to earth in the splendour of the Lord's advent, in which we shall rejoice, and shall be praised, when He says, “Come, you blessed of my Father, inherit the kingdom prepared for you from the foundation of the world.” For “in the Lord,” says the prophet, “shall my soul be praised; the meek shall hear thereof, and be glad.” If it is knowledge through which those who mourn are blessed, inasmuch as they shall be comforted; let us pray that His will may be done as in heaven so in earth, because when the body, which is as it were the earth, shall agree in a final and complete peace with the soul, which is as it were heaven, we shall not mourn: for there is no other mourning belonging to this present time, except when these contend against each other, and compel us to say, “I see another law in my members, warring against the law of my mind;” and to testify our grief with tearful voice, “O wretched man that I am! Who shall deliver me from the body of this death?” If it is fortitude through which those are blessed who hunger and thirst after righteousness, inasmuch as they shall be filled; let us pray that our daily bread may be given to us today, by which, supported and sustained, we may be able to reach that most abundant fullness. If it is prudence through which the merciful are blessed, inasmuch as they shall obtain mercy; let us forgive their debts to our debtors, and let us pray that ours may be forgiven to us. If it is understanding through which the pure in heart are blessed, inasmuch as they shall see God; let us pray not to be led into temptation, lest we should have a double heart, in not seeking after a single good, to which we may refer all our actings, but at the same time pursuing things temporal and earthly. For temptations arising from those things which seem to men burdensome and calamitous, have no power over us, if those other temptations have no power which befall us through the enticements of such things as men count good and cause for rejoicing. If it is wisdom through which the peacemakers are blessed, inasmuch as they shall be called the children of God; let us pray that we may be freed from evil, for that very freedom will make us free, i.e. sons of God, so that we may cry in the spirit of adoption, “Abba, Father.”
39. Nor are we indeed carelessly to pass by the circumstance, that of all those sentences in which the Lord has taught us to pray, He has judged that that one is chiefly to be commended which has reference to the forgiveness of sins: in which He would have us to be merciful, because it is the only wisdom for escaping misery. For in no other sentence do we pray in such a way that we, as it were, enter into a compact with God: for we say, “Forgive us, as we also forgive.” And if we lie in that compact, the whole prayer is fruitless. For He speaks thus: “For if you forgive men their trespasses, your heavenly Father will also forgive you: But if you forgive not men their trespasses, neither will your Father forgive your trespasses.”
Source: Our Lord's Sermon on the Mount (New Advent)