Matthew 6:9

As God is the common Father of all, we pray for all. Let none fear on account of their lowly station here, for all are comprised in the same heavenly nobility.... By saying, "who art in heaven," he does not mean to insinuate that he is there only, but he wishes to withdraw the humble petitioner from earth, and fix his attention on heaven. (St. John Chrysostom, hom. xx.) Other prayers are not forbidden. Jesus Christ prayed in different words (John, chap. viii.), and the apostles; (Acts i, 24,) but this is an example of the simple style to be used in prayer, and is applicable to all occasions. --- Hallowed be thy name, from the word holy, be held and kept holy, be glorified by us, and that not only by our words, but principally by the lives we lead. The honour and glory of God should be the principal subject of our prayers, and the ultimate end of our every action; every other thing must be subordinate to this. (Haydock)