25.15 Confound the superstition of the Greeks, as you did once before, and their polytheistic denial of God, along with their gods old and new and their disgusting myths and more disgusting sacrifices by which they attempt to purify slime with slime, a I heard one of them say (that is, use the bodies of dumb animals to purify their own), and the misshapen and monstrous figments they venerate. If that is their notion of divinity, how perverse! And if, on the one hand, they intend them as illustrations, how absurd! Let them provide an explanation of their reasoning and the divine truth underlying this grotesquerie! Even the superficial portrayals of the beautiful should be free of ugliness. But if they say that something else besides is involved, let them tell us what it is and from what books or theologians it derives. Confound two heresies and their violent outbreaks, and all the more vigorously since you have suffered from them in the past. The philosophical spirit is made more noble by suffering: hardened by trials, like hot steel plunged into cold water. Define too for us our orthodox faith by teaching us to recognise God, unbegotten, the Father, and one begotten Lord, his Son, referred to as God when he is mentioned separately, but Lord when he is named in conjunction with the Father, the one term on account of his nature, the other on account of his monarchy; and one Holy Spirit proceeding, or, if you will, going forth from the Father, God to those with the capacity to apprehend things that are interrelated, but in fact resisted by the impious though so recognised by their betters and actually so predicated by the more spiritual. Neither should we place the Father beneath the first principle, so as to avoid positing first of the first, thus necessarily destroying primary existence; nor say that the Son or the Holy Spirit is without beginning. Thus we shall avoid depriving the Father of his special characteristic. Paradoxically, they are not without beginning, and, in a sense, they are: they are not in terms of causation, since they are indeed from God although they are not subsequent to him, just as light is not subsequent to the sun, but they are without beginning in terms of time since they are not subject to it. Otherwise, that which is transitory would be antecedent to the things that abide, and that which has no independent existence to the things that do.
25.16 Neither should we posit three first principles if we want to avoid the polytheism of the Greeks, nor a single one, Judaic in its narrowness as well as grudging and ineffectual, whether by positing a self-absorbing deity (the preferred view of those who have the Son issue from the Father only to be absorbed into him again) or by disallowing their natures and stripping them of Godhead, as our current experts like to do, as though the Godhead feared some rival opposition from them or could produce nothing higher than the creatures. Likewise, we should not claim that the Son is unbegotten, for the Father is one, nor the Holy Spirit is the Son, for the Only-Begotten Son is one. In this way, the divinity of each will be defined in terms of their property that is unique to each, in the case of the Son, his Sonship, in the case of the Holy Spirit, its procession and not sonship. We should believe that the Father is truly a father, far more truly father, in fact, than we humans are, in that he is uniquely, that is, distinctively so, unlike corporal beings; and that he is one alone, that is without mate, and the Father of one alone, his Only-Begotten; and that he is a Father only, not formerly a son; and that he is wholly Father, and faith of one wholly his Son, as cannot be affirmed of human beings; and that he has been Father from the beginning and did not become Father in the course of things. We should believe that the Son is truly a Son in that he is the only Son of one only Father and only in one way and only a Son. He is not also Father but is wholly Son, and Son of who is wholly Father, and he has been Son from the beginning, since there was never a time when he began to be a Son, for his divinity is not due to a change of purpose nor his deification to progress in time; otherwise, there would be a time when the one was not a Father and the other not a Son. We should also believe that the Holy Spirit is truly holy in that there is no other like it in quality or manner and that its holiness is not conferred but is holiness in the absolute, and in that it is not more or less nor did it begin or will it end in time. For what the Father and Son and Holy Spirit have in common is their divinity and the fact that they were not created, while for the Son and the Holy Spirit it is the fact that they are from the Father. In turn, the special characteristic of the Father is his ingenerate-ness, of the Son his generation and of the Holy Spirit his procession. But if you seek after the means, what will you leave to them—in the words of Scripture, they alone know and are known by one another—or also for those of us who will one day receive illumination from on high?
26.19 Holy Trinity, venerable and perfect, rightly united by us in worship, the successful completion of the noble task lies with you. Those who set themselves far apart from us that the very separation taught them the value of harmony may you restore to us once again; and ourselves in return for our trials here on earth may you reward with the blessings of heaven that are free from faction. The first and greatest of these is to be more fully and more purely enlightened by you in the matter of how, though the same, you are both conceived as unity and seen as trinity; how the unbegotten and begotten and the one that proceeds are one nature but three distinct persons, one God, who is above all and through all and in all, who is not surpassed, or altered, or diminished, or severed; who is in part already comprehended and in part still the object of our quest, yet doubtless one day to be comprehended in all your majesty by those who while on this earth have nobly undertaken the quest through a life of contemplation; to whom be all glory, honour, and power, forever: Amen