The Lord's Prayer in General
1 Q. Which is the most excellent of all vocal prayers?
A. The most excellent of all vocal prayers is that which Jesus Christ taught us, that is to say, the Our Father.
2 Q. Why is the Our Father the most excellent of all prayers?
A. The Our Father is the most excellent of all prayers because Jesus Christ Himself composed it and taught it to us; because it contains clearly and in a few words all we can hope for from God; and because it is the standard and model of all other prayers.
3 Q. Is the Our Father also the most efficacious of prayers?
A. Yes, it is also the most efficacious of prayers, because it is the most acceptable to God, since in it we pray in the very words His Divine Son has taught us.
4 Q. Why is the Our Father called the Lord's prayer?
A. The Our Father is called the Lord's Prayer, precisely because Jesus Christ our Lord has taught it to us with His own lips.
5 Q. How many petitions are there in the Our Father?
A. In the Our Father there are seven petitions preceded by an introduction.
6 Q. Say the Our Father.
A. (1) Our Father who art in Heaven: (2) Hallowed be Thy Name; (3) Thy kingdom come; (4) Thy will be done on earth as it is in heaven; (5) Give us this day our daily bread; (6) And forgive us our trespasses, as we forgive those who trespass against us; (7) And lead us not into temptation; (8) But deliver us from evil. Amen.
7 Q. When invoking God in the beginning of the Lord's Prayer, why do we call Him Our Father?
A. In the beginning of the Lord's Prayer we call God Our Father, to foster confidence in His infinite goodness by the remembrance that we are his children.
8 Q. How can we say that we are the children of God?
A. We are the children of God: first, because He has created us in His own image, and preserves and governs us by His providence; and secondly, because by an Act of special benevolence He has adopted us in Baptism as brothers of Jesus Christ and co-heirs with Him to eternal glory.
9 Q. Why do we call God Our Father and not my Father?
A. We call God Our Father and not my Father, because we are all His children, and hence we should look on and love one another as brothers and pray for one another.
10 Q. God being in every place, why do we say: Who art in heaven?
A. God is in every place; but we say: Our Father who art in heaven, to raise our hearts to heaven, where God manifests His glory to His children.
(Tomorrow, The Lord's Prayer - The First Petition)
Pius X, Pope St.. Catholic Catechism of Saint Pius X (1908) (pp. 44-46). Kindle Edition.