Cathal BarryThe Trinity is revealed in its fullness by the Spirit, writes Cathal Barry
Many religions invoke God as ‘Father’. 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 emphasises 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 by his relationship to his only Son who, reciprocally, is 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 any one to whom the Son chooses to reveal him."(Matthew 11:27)
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". (John 1:1)
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".
Before his Passover, Jesus announced the sending of 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. The Holy Spirit is thus revealed as another divine person with Jesus and 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."