In all his work, Diadochos appears as a true champion of the doctrine of Chalcedon. In fact, his best-known work, "On Spiritual Knowledge and Discrimination" (known as the "Hundred Chapters" or "Hundred Texts"), was written for his monks in reaction to strange doctrines coming from the heretical Messalian sect in Mesopotamia (also known as Euchites). Some authors have misunderstood the role of Saint Macarius in Mesopotamia and concluded that Diadochos wrote this main work against him. This, however, is not the case, as Macarius' role was merely to salvage from within the Messalian heresy those who were there by chance or just misled by the ambiguous discourses of the unorthodox doctrine.