St. Gregory of Nyssa - On the Holy Trinity, On Not Three Gods, On the Faith

To Eustathius.

All you who study medicine have, one may say, humanity for your profession: and I think that one who preferred your science to all the serious pursuits of life would form the proper judgment, and not miss the right decision, if it be true that life, the most valued of all things, is a thing to be shunned, and full of pain, if it may not be had with health, and health your art supplies. But in your own case the science is in a notable degree of double efficacy; you enlarge for yourself the bounds of its humanity, since you do not limit the benefit of your art to men's bodies, but take thought also for the cure of troubles of the mind.

01 On the Holy Trinity and of the Godhead of the Holy Spirit 

02 On "Not Three Gods"

03 On the Faith