With all his rejection of bookish theology, devoid of spiritual experience, with all the insistence on asserting that God is unknowable and ineffable, St. Simeon confessed a strictly Orthodox faith with a true teaching about God, faith and teaching about the Most Holy Trinity above all. He based it on Divine revelation, Holy Scripture, the teaching of the Holy Fathers, but at the same time on his own personal experience, on what God Himself revealed to him. Many times he asserted that his theology was in full accord with what the Church had taught since the time of the apostles, although their teaching, like that of the ancient Fathers, was often forgotten by his contemporaries, and it was his task to remind them of them, especially as far as the spiritual life was concerned. Faith in the Holy Trinity and the doctrine of the Triune God are an example of his attachment to the tradition of the Church and, at the same time, an example of his personal and existential approach to the mystery.

One thing is certain and immediately evident from his writings: the God of St. Simeon is the Trinitarian God, the Father, the Son and the Holy Spirit. Faith in the Trinity is inseparable from apophaticism. "Tell me, then," he says, probably to some theologian of a more intellectual type, whom he could not stand, "you, who are not afraid to investigate that which pertains to the divine nature, do you believe that there is a triune God (τρισυπόστατος), beginningless, uncreated, incomprehensible, unsearchable, invisible, incomprehensible by the intellect, not predicated by a word, and that He was always the same, Who never had the beginning of days, nor seasons, nor ages, but always existing?" [859] He expresses his faith in God thus: "Think and piously confess concerning the Holy, One-in-Essence and Indivisible Trinity, that the Father begets inexpressibly God the Word, Whom He had in the beginning in Himself and has inseparably begotten and above the word, while the Son is begotten, being always inseparable from the begetting Father, co-eternal and in no way separable from Him, but the Holy Spirit proceeds from the Father, being co-natural and united, of one essence with the Father and the Son, as being worshipped and glorified with Them from every breath... Believe... that Their super-essential essence is one Godhead and the Kingdom of the Triune, so that the three Hypostases merge into one, nor are the naturally united ones divided into three, for in each of them the visible is thought (as belonging) to both in one essence and nature, and glory, and one will. Believe that this is one God, the Creator and Creator of all visible and invisible" [860]. In this confession of the Trinitarian faith, the irreproachable patristic Orthodoxy, faith in the three divine hypostases is expressed by St. Simeon simultaneously with the recognition of the absolute incomprehensibility of the divine essence. Moreover, the knowledge of the Trinity is revealed by God Himself, as we have already pointed out elsewhere [861]. Ave. Symeon often returns to Her unity: "For we do not philosophize that there is another and another and another, of another and another nature, separating the undivided Unity (ένάδα) and the Divinity, unwisely deviating into unnatural othernesses, but we have come to know Them as one God, inseparably divided by the Hypostases and inseparably united by the unity of one essence, all in the Hypostases united, and all in the supersubstantial unit tripling. It must be said that the Same is three Persons and one in the unity of essence, that is, nature" (862).

Ave. Simeon argues that the Holy Trinity can be known using rational concepts or on the basis of analogies with the visible world. Study of the Scriptures alone is not enough for this, although in the absence of charismatic experience one must strictly adhere to what is written, and firmly believe it. "What stupidity, what blindness! he says. "And those who wish to impurely delve into the depths of God, and who hasten to theologize, when they hear of God that just as in the three suns there is one mixture of light, so in the Trinity there is one illumination of the Godhead, immediately imagine in their minds three suns united by light, that is, by essence, separated by hypostases, and foolishly believe that they see this Divinity itself, and thus the holy, consubstantial, and indivisible Trinity is made like an example" [863]. The grace of the Most Holy Trinity alone can reveal it: "For as one Father, one His Only-begotten Son, there is one glory of both, known and revealed to all to whom the Son wills, through the Spirit proceeding from the Father" (864). Ave. Symeon expounds his Trinitarian faith, affirming the unity of God, the coexistence of the Hypostases, the procession of the Holy Spirit from the Father, and again rejects the example of the three suns: "These, therefore, know, being moved by the Divine Spirit, the equality and unity of the Son with the Father. Because in the Father they see the Son, and in the Son the Father through the Spirit, as it is written, "I am in the Father, and the Father in Me," that is, that the Spirit dwells with the Father. For if He proceeds from the Father, and the whole Father is in all the Son, the Holy Spirit is also all in Them, and the Father, and the Son, and the Holy Spirit, are one God, worshipped with every breath. And how will you be able to call the One three suns? For if you unite Them, They will be united and the three will be one, and if not, then you have broken the unity. But you will not find the Father without the Son and the Spirit, nor the Son without the Father and the Spirit, nor the Holy Spirit alien to unity with Him from Whom He proceeds. Believe in the Father and the Son in the Spirit, and in the Son of the Father and with the Spirit, and in the Father the co-eternal Son, always existing and abiding and having the Holy Spirit shining together. They are one God, and not three, existing in three hypostases, and always existing, and likewise existing, glorified by infinite powers in one co-nature and kingdom and Divinity. And if in each of Them the general natural features of the divine quality are contemplated, but three are one, and each one is three, which cannot be in the suns" [865].

These theological statements, in which special emphasis is placed on the unity of the Godhead and on the impossibility of expressing the Trinitarian mystery by means of images, are, as it were, the foundation or frame of the Trinitarian spirituality of St. Simeon, his experience of seeing the Trinity, the experience of His revelation in the soul of the believer, His vision and dwelling. Because, in accordance with the Holy Scriptures, St. Simeon asserts that the Trinity dwells in us: "He Himself, the Word of God, with the Father and the Spirit, dwells in them. Each of these therefore becomes a temple of God in feeling and knowledge" [866]. Ave. Simeon insists on the conscious nature of this process. "In this way, the Father and the Son in the Holy Spirit, in those to whom They come and in whom they truly make their abode, are visible and comprehended without doubt, unchangeably, in one light... knowable" [867].

The vision of the Trinity sometimes takes the form of a dialogue: "Then he who is in such a state (of God's love)," says St. Simeon, "comprehends and sees, and behold, the light. Light, however, seems to him to have its beginning from above, but when he searches, he finds that it has neither beginning, nor end, nor middles. When he is perplexed by this, there are Three in the same (τρία έν αΰτω): through Whom, and in Whom, and in Whom (δι' οϋ καί έν ω καί εις δν). And seeing this, he asks to know, and hears clearly: "Behold, I am the Spirit, through whom and in whom is the Son," and "Behold, I am the Son, in whom the Father is." When he becomes even more perplexed, "Look, you see," says the Father. "And I," says the Son, "am in the Father." And the Spirit says, "Indeed I am, for through Me he who sees the Father and the Son sees, and when he sees, he pours out of the things that are seen." Where are they? "In that (place) where neither man nor angel knows, except My one unit (ένάδος) and super-essential essence and nature." "And in me," he says, "how?" "All, entirely, for I am completely inseparable and indivisible, having unity even in Hypostases." "And if you are in me, how and where are you, how do you say that no one knows?" "Because you are a man and limited, I am limited and in place, for I became limited by becoming a man and one of you, but by My inherent nature I am completely invisible, indelineated, formless, inviolable, intangible, immovable, always moving, filling all things, and nowhere in general, neither in you nor in any other of the angels or prophets who are approaching (Me) in ancient or now, by whom I was not seen at all, and never am seen" [868]. This mysterious vision, as St. Simeon himself says, is undoubtedly genuine, but perhaps it is too overloaded with theological terms, [870] moreover, in it not only the three Persons of the Most Holy Trinity, but also the very essence of God speaks in the first person, and this clearly shows that for St. Simeon the theological Trinitarian terms were a living reality.

The Trinity is a treasure hidden in us, which preserves us in our life according to God and helps us in difficulties: "This is a treasure," says St. Simeon in the Catechetical Homilies, "the Holy Trinity, which we contain through ... the exact keeping of all the commandments, which by its love for mankind and power and grace keeps us intact and unyielding and unshakable on all sides, and preserving us, whom, as weak and capable of slipping easily, a few insufficient or mistaken, the treasure itself immediately compresses and unites with itself, and sticks to itself, and makes up for our shortcomings, and strengthens us, and makes us more steadfast" [871]. Ave. Simeon speaks here about the spiritual prerequisites, the fulfillment of the commandments necessary for the possession of the treasure of the Most Holy Trinity. In another place he again returns to the conscious character of this possession: "The indwelling of the Triune Godhead in the perfect is cognitive and clearly perceptible" (872). In the Hymns, St. Simeon speaks of visions of the Trinity that he had, while admitting that it is impossible to tell it. Sometimes he sees three Persons, but only Christ reveals to him the understanding of this vision that was in the darkness. "In the very night and in the very darkness I see Christ, terribly opening the heavens to me, and Himself bowing down and seeing me together with the Father and the Spirit, in the thrice-holy light, being one in three and in one three. They are undoubtedly the light and the light of one three, which above the sun illuminates my soul and envelops my mind, which is in darkness... and therefore a miracle strikes me all the more when (Christ) somehow opens the eye of the mind... For He, the light, appears in the light to those who see, and those who see again see Him in the light. For in the light of the Spirit those who see see, and those who see in Him see the Son, but he who is vouchsafed to see the Son sees the Father, and he who sees the Father sees in any case with the Son. Even now, as I have said, this is happening in me" [873].

To know the Most Holy Trinity and to worship Her is a great blessing, for which St. Simeon thanks God: "I thank Thee that Thou hast granted me to live, and to know Thee, and to worship, O my God, for it is life, to know Thee, the one God, the Creator and Creator of all, unbegotten, uncreated, beginningless, one, and Thy Son, begotten of Thee, and the All-Holy Spirit, the All-Sung Trinitarian Unity (Τριαδικήνά Μονάδα), piously worship Whom and revere Her above all other glory, whether you name earthly or heavenly" [874]. However, as St. Simeon adds, there are very few of those "who are in clear contemplation of Them, who were in the beginning before all ages (begotten) of the Father, with the Spirit of the Son, God and the Word, of the Triple Light in One, and of the One in the Three" (875). Ave. Simeon again affirms the unity of God and the reality of His three Hypostases, using a rather unusual way. "For both are one light: the Father, the Son, and the Spirit, indivisible in three Persons, but united to Them by Divine nature, origin, glory, power, and also will. Because the Three are visible to me as two beautiful eyes filled with light on one face. Without a face, how will the eyes see, tell me? And a face without eyes should not be called so at all, for it lacks the most important or, rather, everything" [876]. Probably, with regard to this image, face and eyes, it can be said that it is no more satisfactory than the image of the three suns, rejected by St. Simeon. But here it is the content of the vision (όράται μοί) that the monk is trying to convey. (However, it bears some resemblance to the image of the two hands of God, the Son and the Spirit, in St. Irenaeus of Lyons.)

Be that as it may, St. Simeon returns to the image of the sun in order to make the life-giving action of the Trinity more visible: "For the sun, if it is deprived of the splendor of light, will first perish itself, and then all creation, which receives from it the opportunity to be illumined and see, in the same way God, if He is deprived in the intellectual (world) of either the Son or the Spirit, will no longer be the Father, from Whom all are given both life and being" [877]. But we worship the Most Holy Trinity in the Holy Spirit: "Glory to Thee, Father, Son, and Holy Soul, Divinity indescribable, indivisible in nature, we all worship Thee in the Holy Spirit, having Thy Spirit, as having received Him from Thee, and seeing Thy glory, and we are not curious, but in Him (the Spirit) we see Thee, the unbegotten Father, and begotten, proceeding from Thee God the Word. Thus we worship the indivisible, unfused Trinity in one Godhead and principle and power. Amen" [878].

Ave. Simeon addresses the Most Holy Trinity as if She were one Person, and calls Her the "God of all": "I saw Thy Face and was afraid, although Thou didst appear to me gracious and approachable, and Thy beauty amazed and amazed me, O Trinity my God! One features of three in each, and Three one Person (πρόσωπον), O my God, Who is called the Spirit, the God of all" [879]. The vision of the Trinity is always a vision of the beauty of God. Or about the ineffable unity of the three Hypostases: "One Father, the Son also with the Divine Spirit, One Three and Three, One God is inexplicable" (880). God is above every name, He is Triune, but One, and His unity is inexpressible. "Even though Thou art called by many different names," says St. Simeon, "yet Thou Thyself is One, and this One is unknown to all nature and invisible and inexpressible, but, partially shown (παραδεικνύμενον), is called by all (names). This is the One (τό εν) Triune nature, one Godhead and one kingdom, one power, for the Trinity is One, because my God is One Trinity, and not Three, but Three One in Hypostases, co-natural with each other by nature, wholly co-powerful, consubstantial, united unmerged above the intellect, but again separated inseparably, Three into One and One into Three" (881). All praise is due to the Most Holy Trinity, because She created the world: "Glory, praise, singing, thanksgiving to Him Who brought all creation from non-existence into existence by one word and by His own will, the God of all, worshipped in the Trinity of Hypostases and one essence! For God is One, the Holy Trinity, the super-substantial essence, One in three Persons and three Hypostases, indivisible and indivisible, one nature, one glory, one power is She, and one will also. She alone is the Creator of everything" [882].

Although God, as has been said, is above every name, the hypostatic names are not arbitrary, and the very order of the Persons in the Trinity cannot be changed. "And if it is necessary to express it more precisely," says St. Simeon in one of the Catechetical Homilies, which is theologically very precise, "then what is One, is also Two. For the Three are in the same and are thought of as one essence and nature and kingdom. That which is called One is by nature contemplated in the others, except the "Father," that is, both the "Son" and the "Holy Spirit." In other words, except for "to beget," there is both "to be born" and "to proceed," because only these (names) follow the Holy Trinity naturally and indisputably by nature. Changes, or reverse movements, or changes of names in them, cannot be thought of or expressed to us. For by means of them the three Persons have become known, and neither the Son can be placed before the Father, nor the Holy Spirit before the Son, but must be said at once, "Father, Son, and Holy Spirit." Moreover, there should be no interruption, not even the smallest one, in time or moment, but together with the Father the Son is begotten and the Spirit is gone" [883]. As for the other divine names, with the exception of hypostatic designations, they are common to the three Persons and are used in the singular, as expressing the unity of God's revelations (a certain contrast to the Latin Filioque can be seen in all these theological explanations). "In all other cases," continues St. Simeon, "one name or example is contemplated both separately and in three. For example, "light," if you say, and each of Them is "light," and the Three are one light; "eternal life" — and each of Them also separately, the Son and the Spirit and the Father, is life, and the Three are one life; The Spirit (is) the Father and God, and the Lord is the Spirit, and God (is) the Holy Spirit. They are God one by one and Three together God. There is one Lord each and three Lords. One God is above all, the Creator of all, separately, and They are the One Creator of all, God" [884].

Ave. Simeon says that this mystery, the mystery of the trinity of God, is given to us by Christ Himself. "One God," he writes, "is and is said, sometimes contemplated and believed as a Unity (μονάς) singular and worshipped by us, and sometimes as a Trinity confessed, trinitarianly glorified in divided Hypostases, as we were initiated into mystery by one of the Triune Godhead, our Lord Jesus Christ Himself, who enjoins us to baptize in the name of the Father, and of the Son, and of the Holy Spirit... By this, therefore, grace enables us to contemplate all the unity of the Triune and consubstantial Godhead and Kingdom, and the identical and identical existence of His Hypostases of eternal glory and indivisible unity, so that we may know that there is the whole Father with the Spirit, where all the Son and God are named, and that there is the whole Son through the Spirit, where all God and the Father are glorified, and that all there is the Holy Spirit, where the whole Father confesses and is glorified with the Son" [885].

The Trinity, which contains everything, reaches every man. "The Holy Trinity," says St. Simeon in the Chapters, "stretching through all, from the first to the last, as from the head of someone to the feet, contains all, and sticks, and unites, and binds to Himself, and, containing (them), makes them solid and indestructible. In each of them She is one and the same and is known, and She is God, in whom the latter become first and the first as last" [886]. The Trinity, which is beyond everything, dwells entirely in man, and this is a great mystery for St. Simeon. "Do not doubt," he says, "He finds a place in one soul with the Father and the Spirit, and the whole soul within Himself. Thoughts, look, consider it! Because I have said that the unbearable and unapproachable light for the angels is within the soul, dwells again in the soul and does not scorch it at all. Have you learned the depth of the mystery? Small among visible things, man, shadow and dust, has all God within him, in whose finger hangs all creation, and everyone has being, life, and motion" (887). The soul with mind and understanding (λόγον) is the image of the Trinity: "Indeed," he says, "the soul of each man is the rational image of the Word... God is the Word from God, co-ordinated with the Father and the Spirit. In the same way, my soul is in His image, for, having mind and word, it possesses them in essence indivisible and unmerged, consubstantial also, and the three are united, but also separated" (888). In this depiction of the Trinity, the Word (Logos) is in the center. But then there is the Spirit in the beginning: "Without the Spirit there will be neither the Father nor His Son, but the Father is the Spirit and His Son... and God is again the Spirit, for They constitute the One in nature and in essence, as mind, soul, and word... As the mind is from my soul, or rather from my soul, so from the Father the Spirit, or rather, He remains in the Father and proceeds inexpressibly" (889). The purpose of these images is

This exact image, although it is a little dark, indicated my word" [890]. But St. Simeon is well aware of the insufficiency of such images and adds that only through the inner purification of the soul can one come to the knowledge of the Trinity: "You will never see this (image) and will never understand it, if you do not first cleanse it, if you do not first wash the dirt from your image, if you do not bring it out, buried in the passions... and you will not whiten like snow" [891]. But purification is not enough, the revelation of the Spirit is also needed! "But when you have done this, and have cleansed yourself well, and have become a perfect image, you will not see the prototype (Πρωτότυπον) and will not understand, unless it is revealed to you by the Holy Spirit" (892). Nevertheless, confession, repentance, tenderness and tears wash the soul from sins, and "it becomes the house of the Divine Trinity and Its dwelling place, seeing its Creator and God purely, and conversing with Him daily, it proceeds from the body and from the world and this air, and, ascending to the heavens of heavens, relieved by the virtues and wings of God's love, rests with all the righteous from its labors and is in the infinite and Divine light, where the ranks of the Apostles of Christ, the martyrs, the monks and all the heavenly powers rejoice together" [893]. Moreover, the whole person, body and soul, unites with God and becomes the image of the Holy Trinity. "Body, soul, and God, these three: God... mixed with a clever soul... in order to save the spirit and immortalize the flesh. This is what He promises, saying: "I will dwell in them and walk in them"... As in the Father, and the Son, and the Holy Spirit, one God is worshipped inseparably and inseparably, so, in turn, in God, both soul and body, man becomes God inseparably and inseparably by grace, and neither the body is changed into soul, nor is the soul changed into divinity, nor God is mixed with the soul, nor the soul is re-frozen into flesh, but God remains God as He is, and the soul as it is by nature, and the body as it was created, is dust... The Father, the Son, and the Holy Spirit, the one God whom we honor. God, soul and body, man, created in the image of God and vouchsafed to be vouchsafed by God" [894]. Thus, a person also becomes a triple hypostasis, as St. Simeon states: "O miracle! Man is united with God spiritually and bodily, since the soul is not separated from the mind, nor from the soul the body, but by unity essentially becomes trihypostatic (τρισυπόστατος) by grace and man, one God according to position (θέσει) from body and soul and the Divine Spirit, to which he has partaked" [895].

St. Simeon does not have a complete exposition of the Church's teaching on the Most Holy Trinity, which he fully shared, but rather some aspects of it that the monk considered the most important for spiritual life, or those that flowed from his visions. He insists, first, on the incomprehensibility and inaccessibility of the Most Holy Trinity, on an apophatic approach to the mystery. Further, with a force that makes us assume that very many have opposed him, the monk affirms the unity of the Triune God, without in any way denying the validity of the divine Hypostases. He also affirms, following the line of St. John of Damascus and St. Photius, the reality of the hypostatic names, the Father, the Son, and the Holy Spirit, and especially their unbearable and uncommunicable character, which is characteristic of each Person, which distinguishes the hypostatic names from the general names denoting the one revelations of the Godhead. On the mystical plane, he sometimes refers to the Holy Trinity as one Person, and the Divine Essence even speaks to him in the first person. On the contrary, the three Hypostases, the Father, the Son, and the Holy Spirit, also speak to him separately. In order to make his beliefs and trinitarian visions more illustrative, St. Simeon uses a number of images, more or less successful and original, such as the face and eyes, or the analogy with the faculties of the soul, the mind, the intellect, the spirit, but rejects others, purely physical, such as the three suns, and admits that all of them are insufficient, and that it is only by the grace bestowed upon those who have been purified, You can understand them. Only very rarely in St. Simeon do we find descriptions of the visions of the Trinity as something different from visions of light, except in the case of the Three Persons conversing with him separately. In contrast to this, he often speaks of the indwelling of the Holy Trinity in man and of Its union not only with the soul, but with the whole man, when man also becomes a threefold image, a triune – body, soul and God, as the third component of this union by grace.