His is a remarkable story of spiritual delusion (prelest in Russian) and repentance of delusion. Nicetas was a young and zealous monk of the Lavra of the Kiev Caves who, against the advice of his abbot St Nikon (March 25), retired alone to a cave and walled himself in. Some time later, the young monk experienced a delightful scent filling his cave. Believing himself to be receiving a divine revelation, he cried out ‘Lord, show Thyself to me, that I might worship Thee face to face!’ A voice answered, ‘I am sending you an angel: do whatever he tells you.’ The Devil soon appeared to him as an ‘angel of light’ and Nicetas, completely taken in, prostrated before him. The Devil ordered him to stop praying and to devote all his time to reading and memorizing the Old Testament. Nicetas obeyed without question. After awhile, the Devil began to reveal to him things that were happening in the outside world, so that the young monk acquired a reputation for prophecy among visitors to his cave. When the Elders of the Caves realized that Nicetas never spoke to his visitors or anyone else of the New Testament, they decided that he was beguiled by the Devil. Breaking down the door of his cave, they drove out the deceiver by their prayers and forcibly took the young hermit back to the monastery.
As soon as the evil angel had been driven off, Nicetas became like a young child: he instantly forgot the entire Old Testament (which he had virtually memorized) and even lost the ability to read, so that he had to be sent to school again. Slowly he returned to himself, realized his former delusion and repented in tears. Thereafter he devoted himself to humility and obedience in the monastic community. Such was his repentance and progress in the virtues that he was later made Bishop of Novgorod. He reposed in peace in 1108 and became known for working many miracles, especially healing of blindness.