A Pilgrim's Catechism
The Occasional Thoughts of a 21st-Century Roman Catholic on Journey
Towards the Reign of God
Andrei Rublev: The Trinity
How is God one and yet three?
God is one. Anything other than God that exists must be contained within God as effect is contained within its cause. And so there is only one God. God knows not only his creatures but himself. That knowledge of himself, the Word, is infinite and therefore the Word too is God. The Word is not created but is one with God in eternity. Since the Word is distinct from God who is the origin of the Word we say that Word or Son is begotten of God as Father. The Father loves not only his creatures but he loves his Word, the Son, and the Son loves the Father. This mutual Love of Father and Son is infinite and therefore this Love too is God. We call this Love the Holy Spirit.
The Father knows the Son and the Father and Son love one another in the Holy Spirit. In the Western Church we say that the Holy Spirit proceeds from the Father and the Son (filioque); in the Eastern Church we say that the Holy Spirit proceeds from the Father.
Father, Son and Holy Spirit are distinct from one another and yet are one. Historically we have therefore called them persons, three persons in one God.
Father, Son and Holy Spirit are not persons in the modern sense which denotes center of consciousness. If there were three centers of consciousness there would be three gods which is a contradiction.
God is one. His being is his act. As there is one being there is one act.
In referring to God’s act in creating, to aid our understanding, we have traditionally assigned aspects of God’s one act to each distinct person. Thus we say that God creates through the Word or Son in the power of the Holy Spirit, that God speaks or reveals himself through the Word, that God shares his divine life with us through the Word in the Holy Spirit. But, in truth, God is one. God’s act is one. It is not the Father, the Son or the Spirit acting outside of himself; it is the one God who acts ad extra.
Traditionally we have assigned the masculine pronoun to God and occasionally the feminine pronoun to the Spirit but God transcends gender. There is no male or female in God.