This paper examines the development of the image of the biblical Joseph (Genesis 37-50) in the Slavonic tradition. Although Joseph appears in the Slavonic Bible and the Christian tradition in many forms, e.g. as a righteous martyr, pious believer, merciful caretaker of the poor, ideal ruler, and as the prefigurement of Jesus Christ, the image of Joseph as a Christian spiritual expert has not been studied methodically. Based on the denomination that medieval Slavic Christians gave to Joseph, i.e. Їѡсифь Прѣкрасни, which literally means, “the most beautiful Joseph,” I argue it refers to his inner beauty, which makes him radiate with divine light and turns him into a spiritual expert in the interpretation of the messages from God. Slavs took over the biblical traditions about Joseph from the Greek translations before enriching them with their own creativity and spirituality. The fact that Їѡсифь Прѣкрасни is clearly the translation of Ἰωσὴφ ὁ Πάγκαλος, and that the Syriac History of Joseph does not exist in Slavonic, precisely because it had never existed in Greek despite its literary quality, supports this premise.