Mahabharata 3.209.18

3.209.18

brahmacārī yatātmā ca satataṃ vipulavrataḥ |
brāhmaṇāḥ pūjayantyenaṃ pākayajñeṣu pāvakam || 18 ||

He is joined with Soma in the secondary oblation of clarified butter and is also called Rathaprabhu, Rathadhwana and Kumbhareta. He begot a son named Siddhi by his wife Sarayu, and enveloped the sun with his splendour and from being the presiding genius of the fire sacrifice he is ever mentioned in the hymns in praise of fire. And the fire Nischyavana praises the earth only; he never suffers in reputation, splendour and prosperity. The sinless fire Satya blazing with pure flame is his son. He is free from all taint and is not defiled by sin, and is the regulator of time. That fire has another name Nishkriti, because he accomplished the Nishkriti (relief) of all blatant creatures here. When properly worshipped he vouchsafes good fortune. His son is called Swana, who is the generator of all diseases; he inflicts severe sufferings on people for which they cry aloud, and moves in the intelligence of the whole universe. And the other fire (Vrihaspati's third son) is called Viswajit by men of spiritual wisdom. The fire, which is known as the internal heat by which the food of all creatures is digested, is the fourth son of Vrihaspati known through all the worlds, O Bharata, by the name of Viswabhuk. He is self-restrained, of great religious merit, and is a Brahmacharin and he is worshipped by Brahmanas at the Paka-sacrifices. The sacred river Gomati was his wife and by her all religious-minded men perform their rites.