The paper focuses on the ethical teachings of Classical Antiquity philosophers in the poetry of Saint Gregory of Nazianzus, especially on the parallels between the author’s work and the Cynics and the Stoics. The syncretic nature of Gregory’s work, reflected in the assimilation of the teachings of ancient philosophical schools and the then expanding Christianity creates conditions for the explanation and highlighting of basic human virtues. Gregory of Nazianzus’ legacy also draws on the teachings of such philosophers as Plato and Aristotle, but he always approaches them from the perspective of a strictly Christian worldview. He understands philosophy as a moral underlying basis from which one can draw inspiration for a virtuous and happy life. Gregory thinks that philosophy cannot harm Christians in the pursuit of a virtuous life. Nevertheless, Christian teachings and God are the highest authority. They stand above all philosophical schools or ideas advanced by specific philosophers. Gregory’s moral poetry thus directs his readers, if they are to deserve eternal life, to follow the commandments, which is possible only if one lives a practical and virtuous life.