We know well that scene in which Jesus questions his disciples about what people think and say about him and what his disciples believe about him. The people had a plurality of opinions about the identity of Jesus: if he was Jeremiah, if he was the resurrected John the Baptist. After his resurrection also followed the questions about the identity of Jesus and, by ricochet, about the identity of God. Jesus is the Son of God, but is he the son of God as an honorific title or does this title imply that Jesus, besides being human, is also divine? And if we say that the title Son of God is not an honorific title, is Jesus as God as the Father or does he enjoy a diluted divinity, as of second rank? And if he is God, is his humanity real or apparent? When Jesus calls God his Father, is this way of speaking an exaggerated pretension or is it a complete expression, since Jesus is the Son of God in human existence? And if we accept that Jesus is the Son of God, was he also the Son before he became man in the womb of the Virgin Mary, or did the Son come into existence when he was born of the Virgin Mary or perhaps later, when he rose from the dead? And if the Father is God and the Son is God, are they then two gods? And if we add the Holy Spirit, who is this character? Is God also equal in divinity to the Father and the Son? So there are not two but three gods? But, on the other hand, there is only one God, how does one combine the claim that there is only one God with a divine presence and activity in three distinct instances, Father, Son and Holy Spirit?
Questions like these were asked by Christians almost from the moment Christ ascended to heaven and sent the Holy Spirit to his disciples. It took centuries of discussion before Christians agreed that they had correctly grasped the identity of God. God has made himself known to us through his works. From the works of God described in Sacred Scripture we come to know God in himself and before our eyes. Our faith in God implies knowing him, knowing who God is and how he has acted, because our own salvation is at stake.
Our God, the Father of our Lord Jesus Christ, is the same God who called Abraham, the same God who appeared to Moses and sent him to lead his people out of slavery in Egypt; he is the same God who anointed David, spoke through the prophets and promised a future Messiah. But, although he is the same, in the New Testament we have come to know God more fully as he is in himself and as he has revealed himself to us. The face of God in the Old Testament is true, but those who lived at that time saw him as if in a fog. We, ourselves, know him fully through the revelation of Jesus Christ, but in comparison to the knowledge of God that we will have in heaven, we too have a certain and true knowledge of God, but it does not yet have the fullness that we will share in his presence.
We confess that our God is one and that He is Trinity. This means that God is especially communicative: he loves and speaks. He is not a god enclosed within himself. Our God has a Word, that is to say, He says Himself and is also capable of saying what does not exist so that it may exist, and therefore He is Creator. When God is said, He manifests Himself to that which is not God, He creates things. God speaks to himself freely and out of love. Moses invites the people of Israel: Inquire into the times of old, investigate from the day God created man on the earth. Was there ever a god who went to seek out a people in the midst of another people, by dint of trials, miracles and wars, with a strong hand and a mighty arm? This quality of God to communicate and express himself reaches such a degree of intensity that God communicated himself to creation by becoming a creature himself, when he became man in the womb of the Virgin Mary. And our God is capable of giving himself and of loving the men he created to the point that he is able to penetrate the interiority of the believer and dwell in man as the Holy Spirit.
When we speak of the Holy Trinity we affirm something about God in himself, but also something about God in relation to us. Because God is one and at the same time Father, Son and Holy Spirit, we believe that there is only one world, one salvation and one heaven. God created us freely, loves us and speaks to us so that we may respond to him and thus be included as participants without our own merit in the divine life. The Holy Spirit himself, at one with our own spirit, bears witness that we are children of God and co-heirs with Christ, since we suffer with him in order to be glorified together with him. God has revealed enough about himself to us through Jesus Christ so that we have a certain and true knowledge of God and a real and consistent participation in his divine life.
According to St. Matthew the Evangelist, Jesus’ last instruction to his disciples was to go into the world to teach all nations what they had learned from Jesus. So that these people would also become disciples of Jesus and receive baptism in the name of the Father and of the Son and of the Holy Spirit. The three names: Father, Son and Holy Spirit appear on an equal footing at the end of the Gospel according to Matthew. Baptizing a person in the name of God the Trinity implies introducing the person being baptized into the dynamics of the work of God the Father, Son and Holy Spirit. In the Creed that we recite every Sunday we proclaim who our God is and what he has done for us. We believe that God the Father is Creator of everything visible and invisible. When I believe that, then I accept the world as a gift from God and declare that I live in a meaningful world because God loves us.
We believe in his Son Jesus Christ, who is our redeemer by his death and resurrection. By saying that I believe, then I accept that in Christ I obtain forgiveness of sins and eternal life. We believe in the Holy Spirit, in the holy Church, in the communion of saints and in eternal life. When I believe that, then I affirm that my Christian existence is sustained by the action of God within me whom I receive in the Church who teaches me to believe, to live holy and to hope for eternal life as the goal and end of my existence. Our life has consistency, meaning and salvation in the Trinity and from the Trinity. That is why we do everything in his name and live in his presence.