Nicene and Post-Nicene Fathers: Series II/Volume XI/John Cassian/Against Nestorius/Book IV/Chapter 7

Chapter VII.

He returns to the former subject, in order to show against the Nestorians that those things are said of the man, which belong to the Divine nature as it were of a Person of Divine nature, and conversely that those things are said of God, which belong to the human nature as it were of a Person of human nature, because there is in Christ but one and a single Personal self.

so following the guidance of the sacred word we may now say fearlessly and unhesitatingly that the Son of man came down from heaven, and that the Lord of Glory was crucified: because in virtue of the mystery of the Incarnation, the Son of God became Son of man, and the Lord of Glory was crucified in (the nature of) the Son of man. What more is there need of? It would take too long to go into details: for time would fail me, were I to try to examine and explain everything which could be brought to bear on this subject. For one who wished to do this would have to study and read the whole Bible. For what is there which does not bear on this, when all Scripture was written with reference to this? We must then say&#8212;as far as can be said&#8212;some things briefly and cursorily, and enumerate rather than explain them, and sacrifice some to save the rest, as for this reason it would certainly be well hurriedly to run through some points, lest one should be obliged to pass over almost everything in silence. The Saviour then in the gospel says that &#8220;the Son of man is come to save what was lost.&#8221; And the Apostle says: &#8220;This is a faithful saying and worthy of all acceptation; that Christ Jesus came into the world to save sinners, of whom I am chief.&#8221; But the Evangelist John also says: &#8220;He came unto his own, and His own received Him not.&#8221; You see then that Scripture says in one place that the Son of man, in another Jesus Christ, in another the Word of God came into the world. And so we must hold that the difference is one of title not of fact, and that under the appearance of different names there is but one Power [or Person]. For though at one time we are told that the Son of man, and at another that the Son of God came into the world, but one Person is meant under both names.