St John Cassian
On the Holy Fathers of Scetis and on Discrimination is a short treatise on the supreme virtue of discrimination or discernment by St. John Cassian as found in the first volume of the English Philokalia. The Philokalic text is a Greek excerpt and summary made by St. Nicodemos of the Holy Mountain from St. Cassian's Latin classic The Conferences. In this beautiful and eminently practical guide for spiritual progress St. John Cassian produces the teaching of the Desert Fathers on the supreme value of discrimation as "the source, root, crown and common bond of all the vritues." Besides explaining how discrimination holds together all spiritual effort in proportion, he offers many practical counsels on how to acquire discernment.