This paper defines the Byzantine altar as a sacred space of participative performance in the mystery of the Eucharist – a paradigm of “timeless re-enactment of the Christian drama.” Reading a series of Byzantine ekphraseis, the paper addresses such concepts as inner vision (theoria), silent or secret prayer, and divine silence, which are at the very centre of the Byzantine altar. The main focus is to investigate the liminal nature of the Mystery, manifested through concealing-revealing devices, which are thresholds in the liturgical participation of the Byzantine subject. Fear and secrecy in front of the Mystery of Divine Presence are anthropological symptoms dominating the imaginary.