There are many versions to this very disturbing story, which illustrates how even the most pious and abstinent of people can be persuaded by Shaitan and fall from grace.
Much of the story is from Israelite accounts. The story took place after the time of Isa AS. Barsisa was a monk and for decades, he used to spend his days and nights in seclusion to dedicate himself to the worship of Allah. He was renowned amongst his people for his piety.