Life under Saint Gurias
When Saint Gurias was sent to the newly established Kazan diocese, the boyar John Zastolsky went with him. Under the spiritual guidance of Saint Gurias, John led a virtuous and pious life: the sources record that he avoided sin, loved truth, and was strictly honest.
John raised his son Nestor in the fear of God. According to the tradition, the youth was an ascetic from childhood — he wore a hair-shirt, kept the fasts, and loved to pray in church. With his father's consent, Nestor was tonsured a monk and given the name Nectarius. He died at a young age and was buried near the grave of Saint Gurias.
John himself was later tonsured into monasticism with the name Jonah. Before his death he left instructions that he too be buried near Saint Gurias. No specific year of tonsure or repose is recorded in the available sources for either Jonah or Nectarius.