Veneration and Commemoration
In the liturgical Service for the Venerable Saints of the Near Caves, Isaiah is named together with Saints Onuphrios, commemorated on July 21, and Sylvester, commemorated on January 2; the three are jointly described as a triple-stranded sling against the demons.
Beyond his principal feast on May 15, he is commemorated on September 28 within the Synaxis of the Venerable Fathers of the Near Caves and again on the Second Sunday of Great Lent. He is to be distinguished from Bishop Isaiah of Rostov, who reposed in 1090 and is also commemorated on May 15.