Day 358: Who Art in Heaven

The symbol of the heavens refers us back to the mystery of the covenant we are living when we pray to our Father. He is in heaven, his dwelling place; the Father's house is our homeland. Sin has exiled us from the land of the covenant, but conversion of heart enables us to return to the Father, to heaven. In Christ, then, heaven and earth are reconciled, for the Son alone "descended from heaven" and causes us to ascend there with him, by his Cross, Resurrection, and Ascension. CCC 2795

In today's reading, the Catechism discusses the expression "who art in heaven" from the Lord's Prayer (Mt 6:9-13). God is omnipresent and not limited to the heavens or any other place. This refers to His ineffable holiness and majesty, unique to the Eternal God. As the People of God (1 Pet 2:9), we have been "hidden with Christ in God" (Col 3:3), by grace and faith in Christ as His ambassadors (2 Cor 5:20), for as long as He wills and with our true homeland in heaven (Phil 3:20). The pagan Romans used to remind their leaders memento mori ("Remember you will die"), which is apropos here as well. No one can say when their gift of life will be taken back, "for you are a mist that appears for a little time and then vanishes" (Jas 4:14). While we tarry here on earth, we cooperate with the graces He gives us and work for the Lord, but it is our fervent hope that in Christ we "shall always be with the Lord" (1 Thes 4:17) "who art in heaven" in the life to come.

The Catechism Compendium summarizes what the phrase “Who art in heaven” means:

This biblical expression does not indicate a place but a way of being: God transcends everything. The expression refers to the majesty, the holiness of God, and also to his presence in the hearts of the just. Heaven, or the Father’s house, constitutes our true homeland toward which we are moving in hope while we are still on earth. “Hidden with Christ in God” (Col 3:3), we live already in this homeland. (#586)

The Catechism Companion Vol III has some good commentary on this:

God does not watch from far away. He is everywhere and especially near to those with humble and repentant souls. Prayer is not merely about information transfer but about becoming people of prayer. We want prayer to transform us. God is present in this moment, in this place. This realization is essential to our prayer journey... Jesus promised to prepare a place for us in the Father's house. God's love for us is personal. As Scripture tells us, Jesus is the Way, the Truth, and the Life. No one comes to the Father except through him, and this is a powerful aspect of prayer. (p. 232)