When His apostles asked Jesus to teach them how to pray, He taught them the “Our Father.” He taught them words to a prayer, but more importantly an attitude of prayer. We call God “Father”… Abba.
I remember accompanying a pilgrimage to the Holy Land as chaplain. We had some break time in a park. There were kids jumping into the pool. Many of them called out “Abba” to their dads to look at them jump. That’s our closeness to God. We can call Him, “Abba”.
In Jesus, we have a new relationship with God. The Catechism of the Catholic Church reminds us: “We can invoke God as “Father” because he is revealed to us by his Son become man and because his Spirit makes him known to us….” #2780
So, as we say at Mass: “We dare to say.”
Again, from the Catechism of the Catholic Church: “This power of the Spirit who introduces us to the Lord’s Prayer is expressed in the liturgies of East and of West by the beautiful, characteristically Christian expression: parrhesia, straightforward simplicity, filial trust, joyous assurance, humble boldness, the certainty of being loved. #2778. By our “Abba.”
Saint James Catholic Church 