¹ In caring for instruction that is most necessary, it is fitting to state briefly, first of all, what is foremost for all to know; I desire that what is the foundation of the salvation of all should be the firm support of our discourse; and that our teaching should begin from where everything that exists originates and from where what did not exist is initiated. Let the belief of the heart open for us the door of discourse, the same belief that has opened the mouths of all rightly believing Christians to the confession of salvation. Therefore, with Christ’s help, let our discourse rightly take its beginning from the origin of human salvation.

² Let everyone who desires to be saved first believe in the first and the last, the one and triune God: one in subsistence, three in substance; one in power, three in person; one in nature, three in name; one in divinity—who is the Father, the Son, and the Holy Spirit, one God, wholly invisible, incomprehensible, ineffable, in whom there is always being, because God is eternal, a Trinity without beginning, without end, and who has always been what He is and will be; for in God there is no change, but always the perfection of the Trinity. That God is one, the Trinity itself testifies in the Law, saying: “Hear, O Israel: The Lord your God is one Lord”. That this one God is a Trinity, the Savior taught in the Gospel, saying: “Go therefore and teach all nations, baptizing them in the name of the Father, and of the Son, and of the Holy Spirit”. By these two testimonies of the two Laws, the faith of believers is established upon two firm supports. Here you have in truth the Trinity in unity and the unity in Trinity. Therefore, in brief, according to the greatness of the matter, we have stated what we believe, and the faith of the heart has produced the confession of the mouth. Against all heresies, this must be firmly held: that the one God cannot be divided or separated, for what He has been in totality, He has always been as He is. Let, therefore, the poisonous and insane madness of all heretics cease when we hear and believe, with God Himself as witness: “Hear, O Israel: The Lord your God is one Lord”. Because He who is one has always been what He is. Yet, so that you may understand His greatness, He spoke in the plural at the creation of the world: “Let us make man in our image and likeness”. But lest you err in number, Christ reveals to you the Father, the Son, and the Holy Spirit, in whose name, as of one God, the entire human race must be baptized. What more need be said about the coeternity of the Trinity? That He is one is sufficiently taught to us. But concerning the truth of the persons of the Father, and of the Son, and of the Holy Spirit, the distinction established by Christ’s command has abundantly instructed the hearers. From these testimonies, I say, every perversity of error is excluded, and through their naming, both the Trinity and unity are attested and confirmed.

³ Since the greatness of the matter forbids us to speak further about these ineffable things, let us firmly hold the truths already stated by faith. For if these few words about God the Trinity do not suffice for someone, more words, even according to Scripture, will not be of benefit. For we have only said that He is one in Trinity and three in unity. But who can speak of His essence? How is He present everywhere and yet invisible? How does He fill heaven and earth and every creature, as it is written: “Do I not fill heaven and earth?” says the Lord. And elsewhere: “The Spirit of God has filled the whole world,” according to the prophet. And again: “Heaven is my throne, and the earth is the footstool of my feet”. God, therefore, is everywhere, wholly immense, and ever near, according to His own testimony about Himself: “I am a God at hand, says the Lord, and not a God afar off”. We do not, therefore, seek God as if He were dwelling far from us, since we are to receive Him within us; for He dwells in us as the soul in the body, provided that we are healthy members of His, that we are not dead in sins, and that we are free from the corruption of a decayed will. Then, truly, He dwells in us, as He said: “I will dwell in them, and walk among them”. If we are found worthy that He should be in us, then in truth we are made alive by Him, as His living members: “For in Him we live, and move, and have our being,” as the Apostle says. Who, I ask, will investigate the highest and ineffable essence of God? Who will search out the depths of God? Who will dare to discuss the eternal principle of the universe? Who will glory in knowing the infinite God, who fills all things and surrounds all things, who penetrates all things and exceeds all things, who contains all things and eludes all things? “Whom no man has seen at any time,” as He is. Therefore, let no one presume to inquire into the unsearchable mysteries of God—what He was, how He was, where He was. These things are ineffable, unsearchable, and inscrutable. Simply and yet firmly, believe that God is as He is and will be as He was, for God is unchangeable.

⁴ Who, then, is God? The Father, the Son, and the Holy Spirit—one God. Seek nothing further about God, for those who wish to understand the deep mysteries of God must first consider nature. The knowledge of the Trinity is rightly compared to the depths of the sea, as the Wise Man says: “And a great depth, who shall find it?”. If, therefore, one wishes to fathom the unfathomable ocean of divine knowledge, let him first carefully observe what is visible, if he can; and as he realizes how little he knows about the hidden things of the sea, let him understand even more how little he can comprehend the depths of the Creator. Let him presume to speak of the Creator less than of the creature, for he who is not capable of understanding lesser things cannot be competent in greater matters. How can one who is not trusted in small things be believed in greater ones? For he who is ignorant of earthly matters—why does he scrutinize heavenly ones? Oh, how vain are those who speak without understanding, as the Apostle says, “neither understanding what they say, nor what they affirm”. How many, alas, attempt to soar high with fragile wings, placing their words in the heavens concerning the Creator, without having first reasoned properly! They rashly presume to teach about the highest mysteries with impure hearts and unclean lips, not understanding that God, the Trinity, is not known by words but by faith, and is understood by the pious faith of a pure heart, not by the vain babblings of the impure. The great Trinity must, therefore, be piously believed and not impiously scrutinized, for the one God, the Trinity, is an unfathomable and incomprehensible ocean. The sky is high, the earth is vast, the sea is deep, and the ages are long, but higher, wider, deeper, and longer is the knowledge by which He who created all from nothing surpasses nature.

⁵ If you wish to know the Creator, understand the creature; if not even that, remain silent about the Creator, but believe in Him. For silent piety is better and wiser than impious talkativeness. It is foolish and impious to turn from faith to empty words about the invisible, inestimable, and incomprehensible Lord. “A great depth, who shall find it?”. Just as the depths of the sea are invisible to human sight, so also the divinity of the Trinity is incomprehensible to human senses. Therefore, if one wishes to know what he ought to believe, let him not think that he can understand more by speaking than by believing. Rather, the wisdom of divinity will flee further from those who seek it through disputations than it was before. Seek, therefore, supreme wisdom not through words of argument but through the perfection of good conduct; not with the tongue, but with faith; from the simplicity of the heart, not from the conjectures of impiety. If, therefore, you seek the ineffable through discussion, it will recede from you further than before; but if you seek it through faith, it will stand firm where it abides—in the gates of wisdom, where it will be seen, at least in part. But it will only be truly grasped when it is believed as invisible and incomprehensible. For God must be believed to be invisible, as He is, though He may be seen in part by a pure heart. Therefore, dearest brothers, let us implore our ever-present, invisible God, that His fear and love—love which never fails—may remain in us. May this fear, joined with love, make us wise in all things, and may piety teach us to be silent about that which surpasses words. For to know God as He is is an unfathomable and inexpressible mystery. He alone knows Himself—what and how great He is. But since He is our God, though invisible to us, we must continually seek Him, knocking often, always holding fast to the deep, infinite, secret, and exalted omnipotent God. Through the merits and intercessions of His saints, let us pray that He may grant us even a small portion of His light to shine upon our ignorance and folly in this dark world, to lead us to Himself, through the gift of our Lord Jesus Christ, to whom, with the Father and the Holy Spirit, be glory forever and ever. Amen.