St. Gregory the Theologian, Oration 2
St. Ambrose of Milan, Three Books on the Duties of the Clergy
St. John Chrysostom, Treatise on the Priesthood
St. Gregory the Great, Book of the Pastoral Rule
On the Priesthood
On the Priesthood
I've been slowly working my way through St. Gregory the Theologian's Second Oration. It is a very humbling to read this! It nearly makes me shake in fear to imagine the burden and responsibility of the priesthood. St. Gregory's personal situation, which he addresses here, is also quite interesting.
I've also enjoyed reading his correspondence with St. Basil.
Ephraem
~He who seeth his own sins, seeth not the sins of others.