"According to the testimony of Holy Scripture, the center of the life and person of Jesus is his constant communication with the Father.” -Benedict XVI
Jesus Christ's “constant communication” with the Father was in prayer. It is in prayer that the revelation of Jesus Christ as the Son is most evident and understood. Paradoxically, it is in the hiddenness of his prayer which most openly expresses the core reality of his personality as “Son” to the apostles and particularly to Peter.
Benedict XVI notes some the numerous titles applicable to Jesus Christ: prophet, priest, rabbi, king, Lord, and Son. But the most appropriate title for Jesus Christ, in light of his constant communication with the Father, is Son. Benedict XVI expresses, "It is the only comprehensible designation for Jesus. It both comprises and interprets everything else.” Thus, the Church’s confession is consistent with Peter’s confession, “You are the Christ, the Son of the living God.”
According to Benedict XVI, whole of Christology lies is Jesus’ prayer. He recalls the Biblical account of Jesus' prayer at the Mount of Olives. Jesus addresses God as "Abba" which in his native language of Aramaic translates to "Daddy" or "Papa." This was a completely novel way to address Father-God. Jewish custom did not refer to God in such an informal manner. The familiarity by which Jesus addressed God was radical, not only for Jews but also for the pagans of the time. The philosophical rationalists had a concept of God, but "a God to whom one could pray" did not exist for them.
Jesus’ entire existence is relationship with the Father. So integral is this understanding of his personhood that Benedict XVI notes that Jesus even died while praying. ("My God, my God, why have you forsaken me?"-Mark 15:34) Jesus was never alone. Benedict XVI writes, “His whole existence until his final cry on the cross was one single act of reaching out to that Other whom he called Father.” The dignity of his being is all rooted in his relationship to God the Father. While Jesus Christ is also "King" and "Lord," the central name that designates his power is “Son.”
His power lies in his total relativity to the Father.
The evangelist Luke recounts the story of Jesus' Transfiguration. His face and clothes are transfigured before the apostles Peter, James, and John. The significance of the transfiguration is that it revealed that Jesus is not only truly human, but also a truly divine being. His divinity is revealed precisely because of the perfection of his communion with the Father. This communion merits the words of God, "This is my Son, my Chosen, listen to him!" (Luke 9:28-36)
The mystery of Jesus becomes visible in his prayer. Benedict XVI explains that in this dialogue of love, “Luke has raised the prayer of Jesus to the central Christological category from which he describes the mystery of the Son.”
It is in the solitary speaking with the Father that he comes to men and that men come to him. This theology of Luke is most clearly expressed in his ironic (yet intentional) choice of words: “when he was alone with the disciples.” (Luke 9:18)
Benedict XVI conveys so eloquently that “only by entering into Jesus’ solitude, only by participating in what is most personal to him, his communication with the Father, can one see what this most personal reality is; only thus can we penetrate to his identity.”
He is Son because of his unceasing prayer. This union and communion signifies his Son-ship to the Father.
Simply put by the God-man, "I and the Father are one." (John 10:30)