Now, as Catholics, we have been given the truth, that God is Three Persons, the Father, the Son, and the Holy Spirit.
Let me quote the CCC here:
234 The mystery of the Most Holy Trinity is the central mystery of Christian faith and life. It is the mystery of God in himself. It is therefore the source of all the other mysteries of faith, the light that enlightens them. It is the most fundamental and essential teaching in the “hierarchy of the truths of faith.”56 The whole history of salvation is identical with the history of the way and the means by which the one true God, Father, Son, and Holy Spirit, reveals himself to men “and reconciles and unites with himself those who turn away from sin.”57 (2157, 90, 1449)
235 This paragraph expounds briefly (I) how the mystery of the Blessed Trinity was revealed, (II) how the Church has articulated the doctrine of the faith regarding this mystery, and (III) how, by the divine missions of the Son and the Holy Spirit, God the Father fulfills the “plan of his loving goodness” of creation, redemption, and sanctification.
236 The Fathers of the Church distinguish between theology (theologia) and economy (oikonomia). “Theology” refers to the mystery of God’s inmost life within the Blessed Trinity and “economy” to all the works by which God reveals himself and communicates his life. Through the oikonomia the theologia is revealed to us; but conversely, the theologia illuminates the whole oikonomia. God’s works reveal who he is in himself; the mystery of his inmost being enlightens our understanding of all his works. So it is, analogously, among human persons. A person discloses himself in his actions, and the better we know a person, the better we understand his actions. (1066, 259)
237 The Trinity is a mystery of faith in the strict sense, one of the “mysteries that are hidden in God, which can never be known unless they are revealed by God.”58 To be sure, God has left traces of his Trinitarian being in his work of creation and in his Revelation throughout the Old Testament. But his inmost Being as Holy Trinity is a mystery that is inaccessible to reason alone or even to Israel’s faith before the Incarnation of God’s Son and the sending of the Holy Spirit. (50)
242 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.66 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.”67 (465)
243 Before his Passover, Jesus announced the sending of “another Paraclete” (Advocate), 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 “into all the truth.”68 The Holy Spirit is thus revealed as another divine person with Jesus and the Father. (683, 2780, 687)
246 The Latin tradition of the Creed confesses that the Spirit “proceeds from the Father and the Son (filioque).” The Council of Florence in 1438 explains: “The Holy Spirit is eternally from Father and Son; He has his nature and subsistence at once (simul) from the Father and the Son. He proceeds eternally from both as from one principle and through one spiration.... And, since the Father has through generation given to the only-begotten Son everything that belongs to the Father, except being Father, the Son has also eternally from the Father, from whom he is eternally born, that the Holy Spirit proceeds from the Son.”75
247 The affirmation of the filioque does not appear in the Creed confessed in 381 at Constantinople. But Pope St. Leo I, following an ancient Latin and Alexandrian tradition, had already confessed it dogmatically in 447,76 even before Rome, in 451 at the Council of Chalcedon, came to recognize and receive the Symbol of 381. The use of this formula in the Creed was gradually admitted into the Latin liturgy (between the eighth and eleventh centuries). The introduction of the filioque into the Niceno-Constantinopolitan Creed by the Latin liturgy constitutes moreover, even today, a point of disagreement with the Orthodox Churches.
248 At the outset the Eastern tradition expresses the Father’s character as first origin of the Spirit. By confessing the Spirit as he “who proceeds from the Father,” it affirms that he comes from the Father through the Son.77The Western tradition expresses first the consubstantial communion between Father and Son, by saying that the Spirit proceeds from the Father and the Son (filioque). It says this, “legitimately and with good reason,”78 for the eternal order of the divine persons in their consubstantial communion implies that the Father, as “the principle without principle,”79 is the first origin of the Spirit, but also that as Father of the only Son, he is, with the Son, the single principle from which the Holy Spirit proceeds.80 This legitimate complementarity, provided it does not become rigid, does not affect the identity of faith in the reality of the same mystery confessed.
The threats to the truth of the Trinity being professed in the world come from three sources. I shall name these in order to show that Catholics must be clear on the teaching of the Trinity, and uphold the doctrine of the Trinity, without error.
First of all, the Muslim religion denies the Trinity. Jesus is not God and there is no Holy Spirit. There is only one god and not Three Divine Persons. Some historians of religion state that the Muslims accepted this simplistic belief as the belief in the Trinity is a mystery and difficult for some people to accept. This interpretation of their denial of a revealed truth given hundreds of years earlier could be true.
Second, I have been reading commentaries from theologians on Vassula Ryden and she confuses the nature of the Three Divine Persons. I suggest going back and looking at my posts which linked two sources explaining the fact that her statements concerning Christ and the Father are at variance with the Catholic Church's teaching.
Some other seers have also confused the Father with the Son, making the Father a material being which He is not. The Father is spirit. Only Christ is Incarnated. The Mormons do not believe that Christ is equal to the Father, that Christ was not always God. And, so on.
Third, New Age "Catholics" and some charismatics do not understand the Church's teaching on the Holy Spirit as coming from the Father and the Son. This indicates, of course, an equality of the Three Persons and the understanding we have of Christ being "consubstantial" with the Father, which we say in the Creed at Mass. Those who think that the Holy Spirit is somehow not connected with Christ want to separate the Second Person of the Blessed Trinity from the Father and the Spirit.
