Bhagavatapurana 4.23.6

4.23.6

grīṣme pañca-tapā vīro varṣāsv āsāraṣāṇ muniḥ /
ākaṇṭha-magnaḥ śiśire udake sthaṇḍile-śayaḥ //

6. In hottest summer he practised austerity, standing in the midst of five fires; the dauntless hero and contemplative sage exposed himself to the heavy downpour of rain during the rainy season; and in winter he stood immersed in water up to his neck and slept on the bare ground.