The article deals with the problem of the ideological origins of Neoplatonism associated with the personality of a little–known Christian theologian, preacher and teacher - Ammonius Sakkas. The material for the article is the works of Neoplatonists and, above all, Plotinus, who, according to Porphyry, studied with Ammonius Saccas for at least eleven years, as well as some works of Porphyry himself. The author uses the possibilities of historical-scientific, philosophical, logical and comparative linguistic methods of analyzing the texts of Plotinus' early works as edited by Porphyry, as well as the method of allegorical interpretation of the texts of Holy Scripture where it seems necessary and contributes to the correct understanding of some philosophical categories and ideas of Neoplatonism, such as the One, Being, Good (Good), concentration, mystical contemplation, ecstasy, being-presence and being-absence, love. As a result of the research, the author comes to the conclusion that Ammonius Sakkas was probably somehow familiar with the sacred theology of St. Dionysius the Areopagite and, most likely, preached it to his disciples. This explains the textual coincidences of individual fragments of the works of Plotinus and Dionysius the Areopagite ("On Divine Names" and "On the heavenly hierarchy"). The interpretation of God as One, Existing (or Truly Existing) – the Father of all and the only source of Good and Goodness reveals an amazing coincidence of their basic semantic content in Plotinus with the Christian metaphysics of the Good News. The author believes that the subject of further research could be a comparison of the features of the sacred theology of Dionysius the Areopagite and the pagan theology of Neoplatonism.