The Heart of the Gospel Witness
In his General Audience on Wednesday, 20 May 1987, the Holy Father finds at the heart of the Gospel the clear teaching that Jesus Christ is the only Son of God.
The cycle of reflections on Jesus Christ has gradually approached its center while remaining in constant relationship with the article of the creed: "I believe in Jesus Christ, the only Son of God." The previous reflections have prepared us for this central truth by showing first of all the messianic character of Jesus of Nazareth. Indeed, the promise of the Messiah--present in the whole revelation of the old covenant as the principal object of the expectations of Israel--finds its fulfillment in him who was accustomed to call himself Son of Man.
In the light of Jesus' words and deeds it becomes ever more clear that he is at the same time the true Son of God. This is a truth which a mentality rooted in a rigid religious monotheism found very difficult to accept. Such was the mentality of the Israelites at the time of Jesus. Our reflections on Jesus Christ now enter the very sphere of this truth which determines the essential newness of the Gospel and the entire originality of Christianity as a religion founded on faith in the Son of God made man for us.
The creeds concentrate on this fundamental truth concerning Jesus Christ. In the Apostles' Creed we profess: "I believe in God, the Father almighty and in Jesus Christ, his only Son." Only later does the Apostles' Creed emphasize the fact that the only-begotten Son of the Father is the same Jesus Christ as Son of Man, "who was conceived by the Holy Spirit, and born of the Virgin Mary."
The Nicene-Constantinopolitan Creed expresses the same thing in slightly different words: "For us men and for our salvation he came down from heaven; by the power of the Holy Spirit he was born of the Virgin Mary, and became man."
Previously in the same creed we find more fully expressed the truth of the divine sonship of Jesus Christ, Son of Man: "I believe in one God, the Father almighty...I believe in one Lord, Jesus Christ, the only Son of God, eternally begotten of the Father, God from God, Light from Light, true God from true God, begotten, not made, one in being with the Father. Through him all things were made." These last words set out still more clearly the unity in divinity of the Son with the Father, who is "the creator of heaven and earth, of all that is, seen and unseen."
The creeds express the Church's faith in a concise manner, but thanks to this very conciseness they stress the more essential truths; those which constitute, as it were, the very "marrow" of the Christian faith, the fullness and summit of God's self-revelation. And so, according to the expression of the author of the Letter to the Hebrews, God "spoke of old...in many and various ways," but last of all "he spoke" to humanity "through his Son" (cf. Heb 1:1-2). It is difficult not to recognize as indicated here the authentic fullness of revelation. God not only speaks of himself by means of men called to speak in his name. But in Jesus Christ, God himself speaking "through his Son" becomes the subject of the revelation. He himself speaks of himself. His word contains in itself God's self-revelation, a self-revelation in the strict and immediate sense.
This self-revelation of God constitutes the great newness and originality of the Gospel. In professing her faith with the words of the creeds, both the Apostles' Creed and the Nicene-Constantinopolitan Creed, the Church draws on the fullness of the Gospel witness and arrives at its essential depth.
In the light of this testimony she professes and bears witness to Jesus Christ as Son, who is "one in Being with the Father." The term "Son of God" could be, and has been, used in a wide sense, as is seen in some texts of the Old Testament such as Wisdom 2:18; Sirach 4:11; Psalm 82:6 and more clearly, 2 Samuel 7:14; Psalm 2:7; Psalm 110:3. The New Testament and especially the Gospels speak of Jesus Christ as Son of God in the strict and full sense. He is "begotten, not made," he is "of the same Being with the Father."
We shall now devote our attention to this central truth of the Christian faith by analyzing the testimony of the Gospel from this point of view. It is above all the Son's witness to the Father and, in particular, the witness of a relation of sonship which is proper to him and to him alone.
In fact, as significant as are the words of Jesus, "No one knows the Father except the Son and any one to whom the Son chooses to reveal him" (Mt 11:27), so likewise are the other words, "No one knows the Son except the Father" (Mt 11:27). Indeed it is the Father who reveals the Son. It is worth noting that in the same context we find Jesus' words, "I thank you, Father, Lord of heaven and earth, that you have hidden these things from the wise and understanding and revealed them to babes" (Mt 11:25; also Lk 20:21-22). The evangelist notes that these words are spoken by Jesus with a particular joy of heart: "rejoicing in the Holy Spirit" (cf. Lk 10:21).
The truth about Jesus Christ, Son of God, belongs therefore to the very essence of the Trinitarian revelation. In it and through it God reveals himself as Unity of the inscrutable Trinity, of the Father, Son and Holy Spirit.
Thus the ultimate source of the testimony which the Gospels (and the whole of the New Testament) give of Jesus Christ as Son of God, is the Father himself, the Father who knows the Son and himself in the Son. In revealing the Father, Jesus shares with us in a certain way the knowledge which the Father has of himself in his eternal, only-begotten Son. By means of this eternal sonship God is eternally Father. Truly in a spirit of faith and joy, and moved with admiration we make our own the words of Jesus: All things have been delivered to you by the Father, O Jesus, Son of God, and no one knows the Son except the Father, nor the Father except the Son and anyone to whom you, O Son, choose to reveal him.
http://www.vatican.va/holy_father/john_paul_ii/audiences/alpha/data/aud19870520en.html