Virtue (arete), excellence of character, is in accordance with human nature, while vice and evil are against nature. Byzantine texts treat of moral subjects by using cliches, maxims, and conventional themes (topoi) that were common in Greek literature and rhetoric; for example, the theme of the man at a crossroad and the choice between a life of virtue and one of vice. Catalogs of virtues and vices were inherited from the Stoic and Platonic tradition and from the Bible, and the Byzantines adopted Greek definitions and classifications. In Fathers like Maximus or Gregory Palamas and also in theologians and philosophers like Psellos, Blemmydes, or Metochites, virtue is connected to knowledge and it serves as a means to the knowledge of God. It is through exercise that human beings can control irrational desire and replace it by rational will. However, in the theological literature the attainment of virtue is not possible by the soul's own faculties, but it is considered as a gift; other thinkers, especially in the Paleologan renaissance, appreciated more the contribution ofreasoning and knowledge to this goal.
Maximus in his Chapters on Love recapitulated the earlier Patristic tradition: to the cardinal (‘‘general’’) virtues of the ‘‘heavenly man’’ - righteousness (justice), moderation, prudence, and courage - the three main theological virtues are introduced: faith, hope, and love. To all these many were added, some in a new Christian sense: philanthropy, piety, humility, mildness, and clemency. Vice (kakia) is a habitually evil disposition, an inclination to wrongdoing and to sin that alienates from God. To the eight sinful desires (logismoi) that named Origen - gluttony, fornication, avarice, grief, wrath, torpor, vainglory, and arrogance - many were added. They belong either to the reasoning faculty, to emotion, or to desire. The vices of reasoning (impiety, heretical opinion, faithlessness, and blasphemy) are worse in effects than those of the two lower parts of the soul, for example, anger, wrath, bitterness, fear, cowardice, zeal, envy, vainglory, or luxuriousness, prostitution, theft, divinations, painting of the face. Reasoning is enlightened when love and charity as well as purity and virtue rule over the two other parts. Intellect is where morality resides since there occur the deliberations of acts; so there could be no actual evil if not a previous evil thought - the sin concerns first of all the intellect.