 Indra, who had lost all hope of recovering his kingdom, went to seek the aid of Vishnu.Vishnu revealed to Indra that only weapons made from the thunder-containing (called in Sanskrit as Vajra) diamond bones of the sage Dadhichi could kill Vritra.Indra and the other Devas therefore approached the sage, whom Indra had once beheaded, and asked him for his aid in defeating Vritra.