Why did Christ command us to call God “our Father”?
To awaken in us at the very beginning of our prayer what should be basic to our prayer— a childlike reverence and trust that through Christ God has become our Father, and that just as our parents do not refuse us the things of this life, even less will God our Father refuse to give us what we ask in faith.
Scripture references
Why the words “in heaven”?
These words teach us not to think of God’s heavenly majesty as something earthly, and to expect everything needed for body and soul from God’s almighty power.