Through penance to Brahma, the demon king Hiranyakashipu won a boon that he could not be killed by day or night, inside or outside a house, by a human or an animal, or by any weapon. Intoxicated by pride, he began calling himself God.
His son Prahlad had been a devotee of Lord Vishnu since childhood and was always chanting “Narayan”. Hiranyakashipu was furious.
He tried to talk Prahlad out of it many times, but Prahlad did not waver. According to the story, he was then thrown from a height, trampled by elephants and given poison, but nothing harmed him.
Holika, Hiranyakashipu’s sister, had a boon that fire could not burn her. She sat on a pyre with Prahlad on her lap, but in the story Prahlad stayed safe while Holika burned. The tradition of Holika Dahan is said to commemorate this.
Finally Hiranyakashipu asked Prahlad, “Is your Vishnu in this pillar too?” Prahlad answered fearlessly, “Yes.” The enraged king struck the pillar and Lord Narasimha emerged from it, half lion and half man.
At twilight, on the threshold, with the demon on his lap, Narasimha killed Hiranyakashipu with his claws. Thus every condition of the boon held, and evil was still ended. Prahlad praised the Lord and later ruled righteously.