VIII.  As to the other passages, My God would be used in respect, not of the Word, but of the Visible Word.  For how could there be a God of Him Who is properly God?  In the same way He is Father, not of the Visible, but of the Word; for our Lord was of two Natures; so that one expression is used properly, the other improperly in each of the two cases; but exactly the opposite way to their use in respect of us.  For with respect to us God is properly our God, but not properly our Father.  And this is the cause of the error of the Heretics, namely the joining of these two Names, which are interchanged because of the Union of the Natures.  And an indication of this is found in the fact that wherever the Natures are distinguished in our thoughts from one another, the Names are also distinguished; as you hear in Paul’s words, “The God of our Lord Jesus Christ, the Father of Glory.” Ephes. i. 17.  The God of Christ, but the Father of glory.  For although these two terms express but one Person, yet this is not by a Unity of Nature, but by a Union of the two.  What could be clearer?