It is certain that you know the story of the Ramayana and you therefore also known that Ravana, the king of Lanka, abducted Sita, Rama’s wife. But you certainly do not know the story of the Sita who was an illusion (maya Sita).
This story clearly illustrates that no harm can come to a person who is righteous.
Thus stirred by Sita’s prayers, Agni appeared and produced a Sita who was really an illusion. This maya sita he left in the real Sita’s place. As for the real Sita, she was absorbed into the fire. Without realising the substitutions, Ravana abducted the illusory Sita and the entire war was fought over a Sita who was not even real.
When Rama triumphed over Ravana and recovered Sita, a test by fire (agni pariksha) was held. In the process, the Sita who was an illusion was returned to the fire and the real Sita emerged once again. Thus the real Sita was never tainted by Ravana’s touch.
(The story of the Sita who was an illusion is also given in the Brahmavaivarta Purana).