Mbh 12.341.11a

"'"The holy one said, 'Do thou, O Brahman, duly think of the courses of acts which creatures are to follow. Thou art the great ordainer of all created Beings. Thou art the master and the lord of the universe. Placing this burthen on thee I shall soon be free from anxiety. At such times, however, when it will be difficult for thee to accomplish the purposes of the deities I shall then appear in incarnate forms according to my self-knowledge.' Having said these words, that grand form with the equine head disappeared then and there. Having received his command, Brahman too proceeded quickly to his own region. It is for this, O blessed one, that the eternal Deity, with the lotus in his navel, became the acceptor of the first share offered in sacrifices and hence it is that He came to be called as the eternal upholder of all Sacrifices. He himself adopted the religion of Nivritti, the end after which those creatures strive that are desirous of indestructible fruits. He ordained at the same time the religion of Pravritti for others, with the view to giving variety to the universe. He is the beginning, He is the middle, and He is the end of all created Beings. He is their Creator and He is their one object of meditation. He is the actor and He is the act. Having withdrawn the universe into Himself at the end of the Yuga, He goes to sleep, and awakening at the commencement of another Yuga, He once more creates the universe, Do you all bow unto that illustrious one who is possessed of high soul and who transcends the three attributes, who is unborn, whose form is the universe, and who is the abode or refuge of all the denizens of heaven. Do you bow unto Him who is the Supreme Lord of all creatures, who is the Lord of the Adityas, and of the Vasus as well. Do you bow unto Him who is the Lord of the Aswins, and the Lord of the Maruts, who is the lord of all the Sacrifices ordained in the Vedas, and the Lord of the Vedangas.