He followed, indeed, chiefly Gregory of Nazianzus, who,
from the great accuracy of his erudition in divine matters, earned the
title “The Theologian,” and who has left scarcely any
chapter of Christian learning untouched in his surviving works, and is
free from any taint or suspicion of the slightest error. John had
read his books with such assiduity that he seemed to hold them all in
the embrace of his faithful memory. Wherefore throughout this
work you may hear not so much John of Damascus as Gregory the
Theologian expounding the mysteries of the orthodox faith. John
further made use of Basil the great, of Gregory of Nyssa, and
especially of Nemesius, bishop of Emesa in Syria, the most beloved of
all; likewise of Cyril of Alexandria, Leo the Great, Leontius of
Byzantium, the martyr Maximus: also of Athanasius, Chrysostom,
Epiphanius, and, not to mention others, that writer who took the name
of Dionysius the Areopagite. Out of all these he culled on every
hand the flower of their opinions, and concocted most sweet honey of
soundest doctrine. For his aim was, not to strike out views of
his own or anything novel, but rather to collect into one single
theological work the opinions of the ancients which were scattered
through various volumes. And, indeed, in order that the reader
may more readily perceive the method of this most careful teacher, we
shall carefully note in the margin the names of the authors and of the
books from which he copied each separate opinion.