The Trinity is a mystery of faith in the strict sense, one of the “mysteries that are hidden in God, which can never be known unless they are revealed by God”. To be sure, God has left traces of his Trinitarian being in his work of creation and in his Revelation throughout the Old Testament. But his inmost Being as Holy Trinity is a mystery that is inaccessible to reason alone or even to Israel’s faith before the Incarnation of God’s Son and the sending of the Holy Spirit.
THE REVELATION OF GOD AS TRINITY
The Father revealed by the Son
Many religions invoke God as “Father”. The deity is often considered the “father of gods and of men”. In Israel, God is called “Father” inasmuch as he is Creator of the world. Even more, God is Father because of the covenant and the gift of the law to Israel, “his first-born son”. God is also called the Father of the king of Israel. Most especially he is “the Father of the poor”, of the orphaned and the widowed, who are under his loving protection.
By calling God “Father”, the language of faith indicates two main things: that God is the first origin of everything and transcendent authority; and that he is at the same time goodness and loving care for all his children. God’s parental tenderness can also be expressed by the image of motherhood, which emphasizes God’s immanence, the intimacy between Creator and creature. The language of faith thus draws on the human experience of parents, who are in a way the first representatives of God for man. But this experience also tells us that human parents are fallible and can disfigure the face of fatherhood and motherhood. We ought therefore to recall that God transcends the human distinction between the sexes. He is neither man nor woman: he is God. He also transcends human fatherhood and motherhood, although he is their origin and standard: no one is father as God is Father.
Jesus revealed that God is Father in an unheard-of sense: He is Father not only in being Creator; he is eternally Father in relation to his only Son, who is eternally Son only in relation to his Father: ‘No one knows the Son except the Father, and no one knows the Father except the Son and anyone to whom the Son chooses to reveal him.”
For this reason the apostles confess Jesus to be the Word: “In the beginning was the Word, and the Word was with God, and the Word was God”; as “the image of the invisible God”; as the “radiance of the glory of God and the very stamp of his nature”.
Following this apostolic tradition, the Church confessed at the first ecumenical council at Nicaea (325) that the Son is “consubstantial” with the Father, that is, one only God with him. The second ecumenical council, held at Constantinople in 381, kept this expression in its formulation of the *Nicene Creed and confessed “the only- begotten Son of God, eternally begotten of the Father, light from light, true God from true God, begotten not made, consubstantial with the Father”.
The Father and the son revealed by the spirit.
Before his Passover, Jesus announced the sending of “another Paraclete” (Advocate), the Holy Spirit. At work since creation, having previously “spoken through the prophets”, the Spirit will now be with and in the disciples, to teach them and guide them “into all the truth”. The Holy Spirit is thus revealed as another divine person with Jesus and the Father.
The eternal origin of the Holy Spirit is revealed in his mission in time. The Spirit is sent to the apostles and to the Church both by the Father in the name of the Son, and by the Son in person, once he had returned to the Father. The sending of the person of the Spirit after Jesus’ glorification reveals in its fullness the mystery of the Holy Trinity.
The apostolic faith concerning the Spirit was confessed by the second ecumenical council at Constantinople (381): “We believe in the Holy Spirit, the Lord and giver of life, who proceeds from the Father.” By this confession, the Church recognizes the Father as “the source and origin of the whole divinity”. But the eternal origin of the Spirit is not unconnected with the Son’s origin: “The Holy Spirit, the third person of the Trinity, is God, one and equal with the Father and the Son, of the same substance and also of the same nature… Yet he is not called the Spirit of the Father alone,… but the Spirit of both the Father and the Son.” The *Creed of the Church from the Council of Constantinople confesses: “With the Father and the Son, he is worshipped and glorified.”
The Latin tradition of the *Creed confesses that the Spirit “proceeds from the Father and the Son (filioque)”. The Council of Florence in 1438 explains: “The Holy Spirit is eternally from Father and Son; He has his nature and subsistence at once (simul) from the Father and the Son. He proceeds eternally from both as from one principle and through one spiration… And, since the Father has through generation given to the only-begotten Son everything that belongs to the Father, except being Father, the Son has also eternally from the Father, from whom he is eternally born, that the Holy Spirit proceeds from the Son.”
The affirmation of the filioque does not appear in the *Creed confessed in 381 at Constantinople. But Pope St. Leo I, following an ancient Latin and Alexandrian tradition, had already confessed it dogmatically in 447, even before Rome, in 451 at the Council of Chalcedon, came to recognize and receive the Symbol of 381. The use of this formula in the *Creed was gradually admitted into the Latin liturgy (between the eighth and eleventh centuries). The introduction of the filioque into the *Niceno-Constantinopolitan Creed by the Latin liturgy constitutes moreover, even today, a point of disagreement with the Orthodox Churches.
At the outset the Eastern tradition expresses the Father’s character as first origin of the Spirit. By confessing the Spirit as he “who proceeds from the Father”, it affirms that he comes from the Father through the Son. The Western tradition expresses first the consubstantial communion between Father and Son, by saying that the Spirit proceeds from the Father and the Son (filioque). It says this, “legitimately and with good reason”, for the eternal order of the divine persons in their consubstantial communion implies that the Father, as “the principle without principle”, is the first origin of the Spirit, but also that as Father of the only Son, he is, with the Son, the single principle from which the Holy Spirit proceeds. This legitimate complementarity, provided it does not become rigid, does not affect the identity of faith in the reality of the same mystery confessed.
ccc 237 – 248