42. The fact of the essence declared to be one in the Father and the Son having one name on account of their similarity of nature seemed to offer an opportunity to heretics to declare that the Unborn God, or a part of Him, was born of Mary. The danger was met by the wholesome resolution that he who declared this should be anathema. For the unity of the name which religion employs and which is based on the exact similarity of their natural essence, has not repudiated the Person of the begotten essence so as to represent, under cover of the unity of name, that the substance of God is singular and undifferentiated because we predicate one name for the essence of each, that is, predicate one God, on account of the exactly similar substance of the undivided nature in each Person.