The formation of the Trinitarian dogma
249 From the beginning, the revealed truth of the Holy Trinity has been at the very root of the Church's living faith, principally by means of Baptism. It finds its expression in the rule of baptismal faith, formulated in the preaching, catechesis and prayer of the Church. Such formulations are already found in the apostolic writings, such as this salutation taken up in the Eucharistic liturgy: "The grace of the Lord Jesus Christ and the love of God and the fellowship of the Holy Spirit be with you all."81
250 During the first centuries the Church sought to clarify her Trinitarian faith, both to deepen her own understanding of the faith and to defend it against the errors that were deforming it. This clarification was the work of the early councils, aided by the theological work of the Church Fathers and sustained by the Christian people's sense of the faith.
251 In order to articulate the dogma of the Trinity, the Church had to develop her own terminology with the help of certain notions of philosophical origin: "substance", "person" or "hypostasis", "relation" and so on. In doing this, she did not submit the faith to human wisdom, but gave a new and unprecedented meaning to these terms, which from then on would be used to signify an ineffable mystery, "infinitely beyond all that we can humanly understand".82
252 The Church uses (I) the term "substance" (rendered also at times by "essence" or "nature") to designate the divine being in its unity, (II) the term "person" or "hypostasis" to designate the Father, Son and Holy Spirit in the real distinction among them, and (III) the term "relation" to designate the fact that their distinction lies in the relationship of each to the others.
The dogma of the Holy Trinity
253 The Trinity is One. We do not confess three Gods, but one God in three persons, the "consubstantial Trinity".83 The divine persons do not share the one divinity among themselves but each of them is God whole and entire: "The Father is that which the Son is, the Son that which the Father is, the Father and the Son that which the Holy Spirit is, i.e. by nature one God."84 In the words of the Fourth Lateran Council (1215), "Each of the persons is that supreme reality, viz., the divine substance, essence or nature."85
254 The divine persons are really distinct from one another. "God is one but not solitary."86 "Father", "Son", "Holy Spirit" are not simply names designating modalities of the divine being, for they are really distinct from one another: "He is not the Father who is the Son, nor is the Son he who is the Father, nor is the Holy Spirit he who is the Father or the Son."87 They are distinct from one another in their relations of origin: "It is the Father who generates, the Son who is begotten, and the Holy Spirit who proceeds."88 The divine Unity is Triune.
255 The divine persons are relative to one another. Because it does not divide the divine unity, the real distinction of the persons from one another resides solely in the relationships which relate them to one another: "In the relational names of the persons the Father is related to the Son, the Son to the Father, and the Holy Spirit to both. While they are called three persons in view of their relations, we believe in one nature or substance."89 Indeed "everything (in them) is one where there is no opposition of relationship."90 "Because of that unity the Father is wholly in the Son and wholly in the Holy Spirit; the Son is wholly in the Father and wholly in the Holy Spirit; the Holy Spirit is wholly in the Father and wholly in the Son."91
256 St. Gregory of Nazianzus, also called "the Theologian", entrusts this summary of Trinitarian faith to the catechumens of Constantinople:
I BELIEVE IN THE HOLY SPIRIT
683 "No one can say 'Jesus is Lord' except by the Holy Spirit."1 "God has sent the Spirit of his Son into our hearts, crying, 'Abba! Father!"'2 This knowledge of faith is possible only in the Holy Spirit: to be in touch with Christ, we must first have been touched by the Holy Spirit. He comes to meet us and kindles faith in us. By virtue of our Baptism, the first sacrament of the faith, the Holy Spirit in the Church communicates to us, intimately and personally, the life that originates in the Father and is offered to us in the Son.
684 Through his grace, the Holy Spirit is the first to awaken faith in us and to communicate to us the new life, which is to "know the Father and the one whom he has sent, Jesus Christ."4 But the Spirit is the last of the persons of the Holy Trinity to be revealed. St. Gregory of Nazianzus, the Theologian, explains this progression in terms of the pedagogy of divine "condescension":
685 To believe in the Holy Spirit is to profess that the Holy Spirit is one of the persons of the Holy Trinity, consubstantial with the Father and the Son: "with the Father and the Son he is worshipped and glorified."6 For this reason, the divine mystery of the Holy Spirit was already treated in the context of Trinitarian "theology." Here, however, we have to do with the Holy Spirit only in the divine "economy."
686 The Holy Spirit is at work with the Father and the Son from the beginning to the completion of the plan for our salvation. But in these "end times," ushered in by the Son's redeeming Incarnation, the Spirit is revealed and given, recognized and welcomed as a person. Now can this divine plan, accomplished in Christ, the firstborn and head of the new creation, be embodied in mankind by the outpouring of the Spirit: as the Church, the communion of saints, the forgiveness of sins, the resurrection of the body, and the life everlasting.
1 1 Cor 12:3.
2 Gal 4:6.
3 St. Irenaeus, Dem. ap. 7: SCh 62, 41-42.
4 In 17:3.
5 St. Gregory of Nazianzus, Oratio theol., 5, 26 (= Oratio 31, 26): PG 36, 161-163.
6 Nicene Creed; see above, par. 465.
The Creed cannot be altered by anyone in particular, regardless what other theological interpretations exist. Which part of this do you not understand?