Against Praxeas by Tertullian
Chapter XXVII.--The Distinction of the Father and the Son, Thus Established, He Now Proves the Distinction of the Two Natures, Which Were, Without Confusion, United in the Person of the Son. The Subterfuges of Praxeas Thus Exposed.
But why should I linger over matters which are so evident, when I ought to be attacking points on which they seek to obscure the plainest proof? For, confuted on all sides on the distinction between the Father and the Son, which we maintain without destroying their inseparable union -- as (by the examples) of the sun and the ray, and the fountain and the river -- yet, by help of (their conceit) an indivisible number, (with issues) of two and three, they endeavour to interpret this distinction in a way which shall nevertheless tally with their own opinions: so that, all in one Person, they distinguish two, Father and Son, understanding the Son to be flesh, that is man, that is Jesus; and the Father to be spirit, that is God, that is Christ. Thus they, while contending that the Father and the Son are one and the same, do in fact begin by dividing them rather than uniting them. For if Jesus is one, and Christ is another, then the Son will be different from the Father, because the Son is Jesus, and the Father is Christ. Such a monarchy as this they learnt, I suppose, in the school of Valentinus, making two -- Jesus and Christ. But this conception of theirs has been, in fact, already confuted in what we have previously advanced, because the Word of God or the Spirit of God is also called the power of the Highest, whom they make the Father; whereas these relations are not themselves the same as He whose relations they are said to be, but they proceed from Him and appertain to Him. However, another refutation awaits them on this point of their heresy. See, say they, it was announced by the angel: |Therefore that Holy Thing which shall be born of thee shall be called the Son of God.| Therefore, (they argue,) as it was the flesh that was born, it must be the flesh that is the Son of God. Nay, (I answer,) this is spoken concerning the Spirit of God. For it was certainly of the Holy Spirit that the virgin conceived; and that which He conceived, she brought forth. That, therefore, had to be born which was conceived and was to be brought forth; that is to say, the Spirit, whose |name should be called Emmanuel which, being interpreted, is, God with us.| Besides, the flesh is not God, so that it could not have been said concerning it, |That Holy Thing shall be called the Son of God,| but only that Divine Being who was born in the flesh, of whom the psalm also says, |Since God became man in the midst of it, and established it by the will of the Father.| Now what Divine Person was born in it? The Word, and the Spirit which became incarnate with the Word by the will of the Father. The Word, therefore, is incarnate; and this must be the point of our inquiry: How the Word became flesh, -- whether it was by having been transfigured, as it were, in the flesh, or by having really clothed Himself in flesh. Certainly it was by a real clothing of Himself in flesh. For the rest, we must needs believe God to be unchangeable, and incapable of form, as being eternal. But transfiguration is the destruction of that which previously existed. For whatsoever is transfigured into some other thing ceases to be that which it had been, and begins to be that which it previously was not. God, however, neither ceases to be what He was, nor can He be any other thing than what He is. The Word is God, and |the Word of the Lord remaineth for ever,| -- even by holding on unchangeably in His own proper form. Now, if He admits not of being transfigured, it must follow that He be understood in this sense to have become flesh, when He comes to be in the flesh, and is manifested, and is seen, and is handled by means of the flesh; since all the other points likewise require to be thus understood. For if the Word became flesh by a transfiguration and change of substance, it follows at once that Jesus must be a substance compounded of two substances -- of flesh and spirit, -- a kind of mixture, like electrum, composed of gold and silver; and it begins to be neither gold (that is to say, spirit) nor silver (that is to say, flesh), -- the one being changed by the other, and a third substance produced. Jesus, therefore, cannot at this rate be God for He has ceased to be the Word, which was made flesh; nor can He be Man incarnate for He is not properly flesh, and it was flesh which the Word became. Being compounded, therefore, of both, He actually is neither; He is rather some third substance, very different from either. But the truth is, we find that He is expressly set forth as both God and Man; the very psalm which we have quoted intimating (of the flesh), that |God became Man in the midst of it, He therefore established it by the will of the Father,| -- certainly in all respects as the Son of God and the Son of Man, being God and Man, differing no doubt according to each substance in its own especial property, inasmuch as the Word is nothing else but God, and the flesh nothing else but Man. Thus does the apostle also teach respecting His two substances, saying, |who was made of the seed of David;| in which words He will be Man and Son of Man. |Who was declared to be the Son of God, according to the Spirit;| in which words He will be God, and the Word -- the Son of God. We see plainly the twofold state, which is not confounded, but conjoined in One Person -- Jesus, God and Man. Concerning Christ, indeed, I defer what I have to say. (I remark here), that the property of each nature is so wholly preserved, that the Spirit on the one hand did all things in Jesus suitable to Itself, such as miracles, and mighty deeds, and wonders; and the Flesh, on the other hand, exhibited the affections which belong to it. It was hungry under the devil's temptation, thirsty with the Samaritan woman, wept over Lazarus, was troubled even unto death, and at last actually died. If, however, it was only a tertium quid, some composite essence formed out of the Two substances, like the electrum (which we have mentioned), there would be no distinct proofs apparent of either nature. But by a transfer of functions, the Spirit would have done things to be done by the Flesh, and the Flesh such as are effected by the Spirit; or else such things as are suited neither to the Flesh nor to the Spirit, but confusedly of some third character. Nay more, on this supposition, either the Word underwent death, or the flesh did not die, if so be the Word was converted into flesh; because either the flesh was immortal, or the Word was mortal. Forasmuch, however, as the two substances acted distinctly, each in its own character, there necessarily accrued to them severally their own operations, and their own issues. Learn then, together with Nicodemus, that |that which is born in the flesh is flesh, and that which is born of the Spirit is Spirit.| Neither the flesh becomes Spirit, nor the Spirit flesh. In one Person they no doubt are well able to be co-existent. Of them Jesus consists -- Man, of the flesh; of the Spirit, God -- and the angel designated Him as |the Son of God,| in respect of that nature, in which He was Spirit, reserving for the flesh the appellation |Son of Man.| In like manner, again, the apostle calls Him |the Mediator between God and Men,| and so affirmed His participation of both substances. Now, to end the matter, will you, who interpret the Son of God to be flesh, be so good as to show us what the Son of Man is? Will He then, I want to know, be the Spirit? But you insist upon it that the Father Himself is the Spirit, on the ground that |God is a Spirit,| just as if we did not read also that there is |the Spirit of God;| in the same manner as we find that as |the Word was God,| so also there is |the Word of God.|