On the Sunday of the Fathers who gathered at the First Ecumenical Council in Nicea in 325, the Church wants to talk to us about the unity of the Father, Son and Holy Spirit in preparation for Holy Pentecost when the Spirit of God will descend upon us.
When people say that God is one, they think it means that He is not two, three, four or ten. That is, they enumerate God. But God cannot be counted. So in this sense it cannot be said that God is one. If you count Him, then you limit Him. God is not one in the numerical sense that we say, for example, that this book is one. There is nothing like God and no number like Him.
In the text from the Gospel that is read today, we see that the Father gave everything to the Son. We do not talk before anything else about God’s unity, rather we talk about the Father. He is the beginning. He is the alpha. The Father poured out everything into the Son and in this sense He is one with the Son. God is one because the Father placed all his life in His beloved Son, in the Word of God that comes out from Him from all eternity. They are one because the life of one is the life of the other because the love in one is in the other. “Everything that is Mine is Yours and everything that is Yours is Mine.” Likewise, we say of the Holy Spirit that everything in the Father belongs to the Holy Spirit and is in the Holy Spirit. The unity in God is the unity of love. God is one because He is love poured out from the Father to the Son and to the Spirit. This love that is in the Father constantly orients Him toward the Son and the love that is in the Son constantly orients Him toward the Father. The Father moves toward the Son and the Son moves toward the Father. There is constant movement in God and this is His unity.
The Father sent His only Son who was eternally in Him so that those who believe in Him will not perish but have eternal life. God put everything in the Son’s humanity: all truth, all purity, all majesty. The fullness of divinity became bodily in the Son and God was one with Christ on earth. This is God’s unity, that He put His whole self in Christ incarnate in the world.
And what is the role of the Holy Spirit in this? The Holy Spirit is the one who distributes Christ’s gifts after He ascended into heaven. He is the one who pours out grace and unites. He is the one who returns the faithful all together to God their Father in prayer, since “the Holy Spirit intercedes for us with groanings that cannot be uttered.”
Thus unity comes down from the Father to the Son and from the Son to the Church and it returns from from the Church to the Father through the Son who does for our sake, rises victorious and ascends to heaven. Unity comes down from above to earth to be reflected from earth back to heaven.
So how is the unity between the faithful, between one person and another? God is one not in order to remain this way but in order to give His unity to people. God exists to be known, not so that He can take pleasure in His own attributes. Unity among humans is for a person to give God to another person. This is the greatest secret in our life. One cannot give a gift greater than that of giving the God that is in him. So if God is not in us, then we cannot give anything. We remain closed off in ourselves and petrified until we are given God through love and we give Him to others through humility. God reaches people through us and He returns to us from people. When He returns to us, He extends Himself to us and takes us into His glory. This is God’s unity in His essence, in His hypostases, in the Church and in the world.