Nicene and Post-Nicene Fathers, Ser. II, Vol. XI: The Wor...
The question what is the difference between the carnal and natural man.
Germanus: You have, it seems to us, very clearly shown the value of the struggle which is raised between the flesh and spirit, so that we can believe that it can in a sort of way be grasped by us; and therefore we want to have this also explained to us in the same way; viz., what is the difference between the carnal and the natural man, or how the natural man can be worse than the carnal.