Catechism #120-121

Question #120: Why did Christ command us to call God “our Father”? 

Answer: At the very beginning of our prayer Christ wants to kindle in us what is basic to our prayer— the childlike awe and trust that God through Christ has become our Father. Our fathers do not refuse us the things of this life; God our Father will even less refuse to give us what we ask in faith (Matt. 7:9-11; Luke 11:11-13). 

Question #121: Why the words “in heaven”? 

Answer: These words teach us not to think of God’s heavenly majesty as something earthly, and to expect everything for body and soul from his almighty power (Jer. 23:23-24; Acts 17:24-25; Matt. 6:25-34; Rom. 8:31-32).