Ascetic Discipline
Theodore's distinguishing labor was the discipline of silence, the practice for which he is surnamed 'the Silent.' The synaxarion relates that he chose this exploit in order to remain continually in the remembrance of God and to safeguard himself from sin committed even through speech.
This emphasis on silence places him within the broader monastic and hesychast tradition cultivated at the Kiev Caves, where inward stillness and watchfulness over the tongue were prized ascetic aims. The synaxarion records that he was granted the gift of wonderworking, though no specific miracles are detailed in the available sources.