Let us continue from yesterday’s QLC, which focused on the general understanding of the Lord’s Prayer. Today, we will examine what the Catechism of the Catholic Church teaches on the very first words of the Lord’s Prayer – “Our Father Who Art in Heaven” –

Simple and faithful trust, humble and joyous assurance are the proper dispositions for one who prays the Our Father. [#2797]

We can invoke God as “Father” because the Son of God made man has revealed him to us. In this Son, through Baptism, we are incorporated and adopted as sons of God. [#2798]

The Lord’s Prayer brings us into communion with the Father and with his Son, Jesus Christ. At the same time it reveals us to ourselves (cf. GS 22 § 1). [#2799]

Praying to our Father should develop in us the will to become like him and foster in us a humble and trusting heart. [#2800]

When we say “Our” Father, we are invoking the new covenant in Jesus Christ, communion with the Holy Trinity, and the divine love which spreads through the Church to encompass the world. [#2801]

“Who art in heaven” does not refer to a place but to God’s majesty and his presence in the hearts of the just. Heaven, the Father’s house, is the true homeland toward which we are heading and to which, already, we belong. [#2802]

For a complete understanding of the first words of the Lord’s Prayer, I would suggest reading paragraphs 2777-2796.