On the Trinity

15. But they who will have these texts understood only of the Father, and not of the Son or the Holy Spirit, declare the Son to be visible, not by having taken flesh of the Virgin, but aforetime also in Himself. For He Himself, they say, appeared to the eyes of the Fathers. And if you say to them, In whatever manner, then, the Son is visible in Himself, in that manner also He is mortal in Himself; so that it plainly follows that you would have this saying also understood only of the Father, viz., “Who only hath immortality;” for if the Son is mortal from having taken upon Him our flesh, then allow that it is on account of this flesh that He is also visible: they reply, that it is not on account of this flesh that they say that the Son is mortal; but that, just as He was also before visible, so He was also before mortal. For if they say the Son is mortal from having taken our flesh, then it is not the Father alone without the Son who hath immortality; because His Word also has immortality, by which all things were made. For He did not therefore lose His immortality, because He took mortal flesh; seeing that it could not happen even to the human soul, that it should die with the body, when the Lord Himself says, “Fear not them which kill the body, but are not able to kill the soul.” Or, forsooth, also the Holy Spirit took flesh: concerning whom certainly they will, without doubt, be troubled to say—if the Son is mortal on account of taking our flesh—in what manner they understand that the Father only has immortality without the Son and the Holy Spirit, since, indeed, the Holy Spirit did not take our flesh; and if He has not immortality, then the Son is not mortal on account of taking our flesh; but if the Holy Spirit has immortality, then it is not said only of the Father, “Who only hath immortality.” And therefore they think they are able to prove that the Son in Himself was mortal also before the incarnation, because changeableness itself is not unfitly called mortality, according to which the soul also is said to die; not because it is changed and turned into body, or into some substance other than itself, but because, whatever in its own selfsame substance is now after another mode than it once was, is discovered to be mortal, in so far as it has ceased to be what it was. Because then, say they, before the Son of God was born of the Virgin Mary, He Himself appeared to our fathers, not in one and the same form only, but in many forms; first in one form, then in another; He is both visible in Himself, because His substance was visible to mortal eyes, when He had not yet taken our flesh, and mortal, inasmuch as He is changeable. And so also the Holy Spirit, who appeared at one time as a dove, and another time as fire. Whence, they say, the following texts do not belong to the Trinity, but singularly and properly to the Father only: “Now unto the King eternal, immortal, and invisible, the only wise God;” and, “Who only hath immortality, dwelling in the light which no man can approach unto; whom no man hath seen, nor can see.”

16. Passing by, then, these reasoners, who are unable to know the substance even of the soul, which is invisible, and therefore are very far indeed from knowing that the substance of the one and only God, that is, the Father and the Son and the Holy Spirit, remains ever not only invisible, but also unchangeable, and that hence it possesses true and real immortality; let us, who deny that God, whether the Father, or the Son, or the Holy Spirit, ever appeared to bodily eyes, unless through the corporeal creature made subject to His own power; let us, I say—ready to be corrected, if we are reproved in a fraternal and upright spirit, ready to be so, even if carped at by an enemy, so that he speak the truth—in catholic peace and with peaceful study inquire, whether God indiscriminately appeared to our fathers before Christ came in the flesh, or whether it was any one person of the Trinity, or whether severally, as it were by turns.