Simple and faithful trust, humble and joyous assurance are the proper dispositions for one who prays the Our Father.
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.
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.1
Praying to our Father should develop in us the will to become like him and foster in us a humble and trusting heart.
Cf. GS 22 § 1.