Chapter IV.--Concerning the manner of the Mutual Communication [1985] .
Now we have often said already that essence is one thing and subsistence another, and that essence signifies the common and general form [1986] of subsistences of the same kind, such as God, man, while subsistence marks the individual, that is to say, Father, Son, Holy Spirit, or Peter, Paul. Observe, then, that the names, divinity and humanity, denote essences or natures: while the names, God and man, are applied both in connection with natures, as when we say that God is incomprehensible essence, and that God is one, and with reference to subsistences, that which is more specific having the name of the more general applied to it, as when the Scripture says, Therefore God, thy God, hath anointed thee [1987] , or again, There was a certain man in the land of Uz [1988] , for it was only to Job that reference was made.
Therefore, in the case of our Lord Jesus Christ, seeing that we recognise that He has two natures but only one subsistence compounded of both, when we contemplate His natures we speak of His divinity and His humanity, but when we contemplate the subsistence compounded of the natures we sometimes use terms that have reference to His double nature, as "Christ," and "at once God and man," and "God Incarnate;" and sometimes those that imply only one of His natures, as "God" alone, or "Son of God," and "man" alone, or "Son of Man;" sometimes using names that imply His loftiness and sometimes those that imply His lowliness. For He Who is alike God and man is one, being the former from the Father ever without [1989] cause, but having become the latter afterwards for His love towards man [1990] .
When, then, we speak of His divinity we do not ascribe to it the properties of humanity. For we do not say that His divinity is subject to passion or created. Nor, again, do we predicate of His flesh or of His humanity the properties of divinity: for we do not say that His flesh or His humanity is uncreated. But when we speak of His subsistence, whether we give it a name implying both natures, or one that refers to only one of them, we still attribute to it the properties of both natures. For Christ, which name implies both natures, is spoken of as at once God and man, created and uncreated, subject to suffering and incapable of suffering: and when He is named Son of God and God, in reference to only one of His natures, He still keeps the properties of the co-existing nature, that is, the flesh, being spoken of as God who suffers, and as the Lord of Glory crucified [1991] , not in respect of His being God but in respect of His being at the same time man. Likewise also when He is called Man and Son of Man, He still keeps the properties and glories of the divine nature, a child before the ages, and man who knew no beginning; it is not, however, as child or man but as God that He is before the ages, and became a child in the end. And this is the manner of the mutual communication, either nature giving in exchange to the other its own properties through the identity of the subsistence and the interpenetration of the parts with one another. Accordingly we can say of Christ: This our God was seen upon the earth and lived amongst men [1992] , and This man is uncreated and impossible and uncircumscribed.
[1985] Cf. Athan., De Salut. adv. Christi; Greg. Naz., Orat. 38; Greg. Nyss., Contr. Apoll.; Leont., Contr. Nestor. et Eutych., bk. 1; Thomas Aquinas, III., quæst. 16, art. 4, 5.
[1986] eidos, form, class, species.
[1987] Ps. xlv. 7.
[1988] Job i. 1.
[1989] aei anaitios ek Patros.
[1990] Greg. Naz., Orat. 35.
[1991] 1 Cor. ii. 8.
[1992] Baruch iii. 38: these words are absent in many mss.
Chapter V.--Concerning the number of the Natures.
In the case, therefore, of the Godhead [1993] we confess that there is but one nature, but hold that there are three subsistences actually existing, and hold that all things that are of nature and essence are simple, and recognise the difference of the subsistences only in the three properties of independence of cause and Fatherhood, of dependence on cause and Sonship, of dependence on cause and procession [1994] . And we know further that these are indivisible and inseparable from each other and united into one, and interpenetrating one another without confusion. Yea, I repeat, united without confusion, for they are three although united, and they are distinct, although inseparable. For although each has an independent existence, that is to say, is a perfect subsistence and has an individuality of its own, that is, has a special mode of existence, yet they are one in essence and in the natural properties, and in being inseparable and indivisible from the Father's subsistence, and they both are and are said to be one God. In the very same way, then, in the case of the divine and ineffable dispensation [1995] , exceeding all thought and comprehension, I mean the Incarnation of the One God the Word of the Holy Trinity, and our Lord Jesus Christ, we confess that there are two natures, one divine and one human, joined together with one another and united in subsistence [1996] , so that one compound subsistence is formed out of the two natures: but we hold that the two natures are still preserved, even after the union, in the one compound subsistence, that is, in the one Christ, and that these exist in reality and have their natural properties; for they are united without confusion, and are distinguished and enumerated without being separable. And just as the three subsistences of the Holy Trinity are united without confusion, and are distinguished and enumerated without being separable [1997] , the enumeration not entailing division or separation or alienation or cleavage among them (for we recognise one God the Father, the Son and the Holy Spirit), so in the same way the natures of Christ also, although they are united, yet are united without confusion; and although they interpenetrate one another, yet they do not permit of change or transmutation of one into the other [1998] . For each keeps its own natural individuality strictly unchanged. And thus it is that they can be enumerated without the enumeration introducing division. For Christ, indeed, is one, perfect both in divinity and in humanity. For it is not the nature of number to cause separation or unity, but its nature is to indicate the quantity of what is enumerated, whether these are united or separated: for we have unity, for instance, when fifty stones compose a wall, but we have separation when the fifty stones lie on the ground; and again, we have unity when we speak of coal having two natures, namely, fire and wood, but we have separation in that the nature of fire is one thing, and the nature of wood another thing; for these things are united and separated not by number, but in another way. So, then, just as even though the three subsistences of the Godhead are united with each other, we cannot speak of them as one subsistence because we should confuse and do away with the difference between the subsistences, so also we cannot speak of the two natures of Christ as one nature, united though they are in subsistence, because we should then confuse and do away with and reduce to nothing the difference between the two natures.
[1993] Leont., Resp. ad argum. Sever.
[1994] For kai te aitiate kai hu& 187;ke, kai te aitiate kai ekporeute we get kai te aitiatike, kai hu& 187;ke, kai poreute in Cod. Colb. 1, Cod. Reg. 3, and so Faber also.
[1995] oikonomias, incarnation.
[1996] Leont., Resp. ad argum. Sever.
[1997] See Leont., Act. 7. De Sect., with reference to one of the arguments of the Nestorians; also Greg. Naz., Orat. 36; Max., Ep. 1 ad Joan. Cubic.
[1998] Infr. ch. vii.: Basil, Epist. 40 and Bk. De Spir. Sanct. ch. 17.