5 “Do ye therefore say,” says he, “Our Father, which art in heaven.” Where ye see you have begun to have God for your Father. You will have Him, when you are new born. Although even now before you are born, you have been conceived of His seed, as being on the eve of being brought forth in the font, the womb as it were of the Church. “Our Father, which art in heaven.” Remember then, that you have a Father in heaven. Remember that you were born of your father Adam unto death, that you are to be born anew of God the Father unto life.
And what ye say, say in your hearts. Only let there be the earnest affection of prayer, and there will be the effectual answer of Him who hears prayer. “Hallowed be your Name.” Why do you ask, that God's Name may be hallowed? It is holy. Why then do you ask for that which is already holy? And then when you ask that His Name may be hallowed, do you not as it were pray to Him for Him, and not for yourself? No. Understand it aright, and it is for your own self you ask. For this you ask, that what is always in itself holy, may be hallowed in you. What is “be hallowed?” “Be accounted holy,” be not despised. So then you see, that the good you wish, you wish for your own self. For if you despise the Name of God, for yourself it will be ill, and not for God.
Source: Sermons on Selected Lessons of the New Testament (New Advent)