Mahabharata Aswamedha Parva Chapter 51

Mahabharata Aswamedha Parva (Anugita Parva) Chapter 51 Brahma said, "Since the mind is the ruler of these five elements, in the matter of controlling and bringing them forth, the mind, therefore, is the soul of the elements. The mind always presides over the great elements. The understanding proclaims power, and is called the Kshetrajna. The mind yokes the senses as a charioteer yokes good steeds. The senses, the mind, and the understanding are always joined to the Kshetrajna. The individual soul, mounting the chariot to which big steeds are yoked and which has the understanding for the reins, drives about on all sides. With all the senses attached to it (for steeds), with the mind for the charioteer, and the understanding for the eternal reins, exists the great Brahman-car. Verily, that man endued with learning and wisdom who always understands the Brahman-car in this way, is never overwhelmed by delusion in the midst of all entities. This forest of Brahman begins with the Unmanifest and ends with gross objects. It includes mobile and immobile entities, and receives light from the radiance of the sun and the moon, and is adorned with planets and constellations. It is decked, again, on all sides with nets of rivers and mountains. It is always embellished likewise by diverse kinds of waters. It is the means of subsistence for all creatures. It is, again, the goal of all living creatures. In that forest the Kshetrajna always moves about. Whatever entities exist in this world, mobile and immobile, are the very first to be dissolved away. After this (are dissolved) those qualities which compose all entities. After the qualities (are dissolved) the five elements. Such is the gradation of entities. Gods, men, Gandharvas, Pisachas, Asuras, and Rakshasas, have all sprung from Nature, and not from actions, not from a cause. The Brahmanas, who are creators of the universe, are born here again and again. All that springs from them dissolves, when the time comes, in those very five great elements like billows in the ocean. All the great elements are beyond those elements that compose the universe. He that is released from those five elements goes to the highest goal. The puissant Prajapati created all this by the mind only. After the same manner Rishis attained to the status of deities by the aid of penance. After the same manner, those who have achieved perfection, who were capable of the concentration of Yoga, and who subsist on fruits and roots, likewise perceive the triple world by penance. Medicines and herbs and all the diverse sciences are acquired by means of penance alone, for all acquisition has penance for its root.