Mbh 12.210.3a

"'"The preceptor said, 'Listen, O disciple, O thou of great wisdom! This that thou hast asked me is undisclosed in the very Vedas and is the highest subject for thought or discourse. It is called Adhyatma and is the most valuable of all branches of learning and of all sacred institutes. Vasudeva is the Supreme (cause) of the universe. He is the origin of the Vedas (viz., Om). He is Truth, Knowledge, Sacrifice, Renunciation, Self-restraint, and Righteousness. Persons conversant with the Vedas know Him as All-pervading, Eternal, Omnipresent, the Creator and the Destroyer, the Unmanifest, Brahma, Immutable. Hear now the story of Him who took his birth in Vrishni's race. A Brahmana should hear of the greatness of that God of gods, viz., Him called Vishnu of immeasurable energy, from the lips of Brahmanas. A person of the royal order should hear it from persons of that order. One who is a Vaisya should hear it from Vaisyas, and a high-souled Sudra should hear it from Sudras. Thou deservest to hear it. Listen now to the auspicious account of Krishna, that narrative which is the foremost of all narratives. Vasudeva is the wheel of Time, without beginning and without end. Existence and Non-existence are the attributes by which His real nature is known. The universe revolves like a wheel depending upon that Lord of all beings. O best of men, Kesava, that foremost of all beings, is said to be that which is Indestructible, that which is Unmanifest, that which is Immortal, Brahma, and Immutable. The highest of the high, and without change or deterioration himself, he created the Pitris, the gods, the Rishis, the Yakshas, the Rakshasas, the Nagas, the Asuras, and human beings. It is He who also created the Vedas and the eternal duties and customs of men. Having reduced everything into non-existence, he once more, in the beginning of a (new) yuga, creates Prakriti (primordial matter).