Mbh 12.205.1b

The Understanding flowing from Ignorance, and possessed of the senses and attributes, runs towards external objects, like a river issuing from a mountain summit and flowing towards other regions. When the Understanding, withdrawn into the mind, succeeds in absorbing itself into contemplation that is free from attributes, it attains to a knowledge of Brahma like the touch of gold on a touchstone. The mind is the apprehender of the objects of the senses. It must first be extinguished (before Brahma can be attained). Dependent upon the attributes of objects that are before it, the mind can never show that which is without attributes. Shutting up all the doors constituted by the senses, the Understanding should be withdrawn into the mind. In this state, when absorbed in contemplation, it attains to the knowledge of Brahma. As the fivefold great creatures (in their gross form) upon the destruction of the attributes by which they are known, become withdrawn (into their subtile form called Tanmatra), after the same manner the Understanding may dwell in the mind alone, with the senses all withdrawn from their objects. When the Understanding, though possessed of the attribute of certainty, dwells in the mind, busied with the internal, even then it is nothing but the mind (without being anything superior to it). When the mind or consciousness, which attains to excellence through contemplation, succeeds in identifying attributes with what are considered as their possessors, then can it cast off all attributes and attain to Brahma which is without attributes.[694] There is no indication that is fit enough for yielding a knowledge of what is Unmanifest (Brahma). That which cannot form the subject of language, cannot be acquired by any one. With cleansed soul, one should seek to approach the Supreme Brahma, through the aid afforded by penances, by inferences, by self-restraint, by the practices and observances as laid down for one's own order, and by the Vedas.