Once, after having defeated the demons the deities had become very arrogant and proud. They started indulging in self praise. Suddenly they were started by the emergence of radiant light before them. All the deities became scarred and went to Indra. Indra sent Vayu to test the power of that radiant light. As soon as Vayu reached there, he found that he had become powerless. One by one all the deities came but returned after being defeated. At last Indra himself went there.
As soon as Indra reached there, he found that he had become bereft of all his powers.
Suddenly goddess Uma manifested herself and warned Indra against becoming arrogant. Indra realized his mistake.