[…] “B. Meaning of who art in Heaven PP.113-114
Such also is the greatness of His power that He says, Who art in Heaven. Thus it is written: ‘Unto Thee have I lifted up mine eyes, who dwelleth in the heavens.’ Ps. 122:1.
The phrase who art in Heaven may be taken to refer to three things:
1. The glory of Heaven (which prepares him who prays).
Who art in Heaven prepares the man who prays. ‘Before prayer, prepare thy soul.’ Sirach 18:23. In this way, in Heaven signifies the glory of Heaven: ‘Your reward is very great in Heaven.’ 1Cor. 15:49.
We should prepare for prayer:
a. By imitating heavenly things, for a son should imitate his father. ‘As we have borne the image of the earthly, let us bear the image of the heavenly.’ Matt. 5:12.
b. By contemplating heavenly things, for a man is wont to turn his thoughts more often toward where his father is and where the things he loves are: ‘Wheresoever thy treasure is, there also is thy heart.’ Matt. 6:21.
c. By searching for heavenly things, so that from Him who is in Heaven we seek nothing but what is heavenly: ‘Seek the things that are above where Christ is.’ Philippians 3:20. ” […]
The Aquinas Catechism by Thomas Aquinas, Ralph McInerny
Originally published as two books: “The Three Greatest Prayers,” and “God’s Greatest Gifts.”