The epistemological discussion of saint Nicolas Cabasilas is entirely founded on his liturgical-sacramental discourse. The natural human cognitive capacity is seen exclusively in the context of the Eucharistic offering – on the one hand it contributes to the preparation of the Christians for the Communion, on the other hand it contributes to the preservation of the sanctification received through the Communion. In the same time Cabasilas founds the discussion about the human cognition in one wider sacramental context, whereas he confronts the knowledge received outside the Sacraments and the one received through the Sacraments. This text has an aim to compare the both contexts in which Cabasilas carries out his epistemological discussion, whereby his different classifications of knowledge will be observed.