An Exposition of the Orthodox Faith 48

1 BOOK III — CHAPTER 4: Concerning the manner of the Mutual Communication.

2 Now we have often said already that essence is one thing and subsistence another, and that essence signifies the common and general form 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.

3 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. For He Who is alike God and man is one, being the former from the Father ever without cause, but having become the latter afterwards for His love towards man.

4 When, then, we speak of His divinity we do not ascribe to it the properties of humanity. Nor, again, do we predicate of His flesh or of His humanity the properties of divinity. 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. 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.