Mbh 13.85.10b

Verily, beholding that sacrifice of the high-souled Mahadeva who had assumed the form of Varuna, all of them became highly pleased. Seeing the celestial damsels of great beauty, the seed of Brahman came out and fell upon the earth. In consequence of the seed having fallen on the dust, Pushan (Surya) took up that dust mixed with the particles of seed from the earth with his hands and cast it into the sacrificial fire. Meanwhile, the sacrifice with the sacred fire of blazing flames was commenced and it went on. Brahman (as the Hotri) was pouring libations on the fire. While thus employed, the grandsire became excited with desire (and his seed came out). As soon as that seed came out, he took it up with the sacrificial ladle and poured it as a libation of ghee, O delighter of the Bhrigus, with the necessary Mantras, on the blazing fire. From that seed, Brahman of great energy caused the four orders of creatures to spring into existence. That seed of the Grandsire was endued with the three attributes of Sattwa, Rajas, and Tamas. From that element in it which represented the principle of Rajas, sprang all mobile creatures endued with the principle of Pravritti or action.[390] From the element of Tamas in it, sprang all immobile creatures. The principle of Sattwa, however, which dwelt in that seed, entered both kinds of existences. That attribute of Sattwa is of the nature of Tejas or Light (being identical with Buddhi or the Understanding). It is eternal and of it is unending Space.[391] In all creatures the attribute of Sattwa is present and is identical with that light which shows what is right and what is wrong. When the seed of Brahman was thus poured as a libation on that sacrificial fire, there sprang from it, O mighty one, three beings into existence. They were three male persons, endued with bodies that partook of the characters of the circumstances from which they respectively sprang.