Devibhagavatapurana 11.24.70

11.24.70

ekapādo japedūrdhvabāhū ruddhvānilaṃ vaśaḥ |
māsaṃ śatamavāpnoti yadicchediti kauśikaḥ ||

Vis’vâmitra Risi says:-- Standing on one leg, with both hands raised and controlling Vâyu he who repeats daily one hundred Gâyatrîs for one month, gets all his desires fulfilled. Similarly with three hundred or thousand repeatings, all things are attained. Submerged under water, if one repeats Gâyatrîs as many times as mentioned above, he gets everything. If, for one year, with hands uplifted and without holding anything, anyone stands on one leg, controls one’s breath and repeats Gâyatrî mantra three hundred times or thousand times, eating Havisyânnam only in the night time, he becomes a Risi (Seer). This thing repeated two years gives infallible speech; three years gives knowledge of the present, past and future; four years will enable one to see face to face the Solar God; five years will give the eight Siddhis, lightness, etc., six years will enable one to assume forms as he desires; seven years gives immortality; nine years gives Manuhood; ten years gives Indrahood; eleven years gives Brahmâ-hood; and twelve years gives the state of Parama Brahma.