Mbh 5.43.15a

“‘The fruits of knowledge are visible; asceticism yieldeth fruits hereafter. A Brahmana who (without knowledge and asceticism) hath only read much should only be known as a great reader. Therefore, O Kshatriya, never think that one can be a Brahman (Brahman-knowing) by only reading the scriptures. He, on the other hand, should be known by thee to be possessed of the knowledge of the Brahman who doth not deviate from Truth. O Kshatriya, the verses that were recited by Atharvan to a conclave of great sages, in days of old, are known by the name of Chhandas. They are not be regarded as acquainted with the Chhandas who have only read through the Vedas, without having attained to the knowledge of Him who is known through the Vedas. The Chhandas, O best of men, become the means of obtaining Brahman independently and without the necessity of anything foreign. They cannot be regarded as acquainted with the Chhandas who are acquainted only with the modes of sacrifice enjoined in the Vedas. On the other hand, having waited upon those that are acquainted with the Vedas, have not the righteous attained to the Object that is knowable by the Vedas? There is none who hath truly caught the sense of the Vedas or there may be some who have, O king, caught the sense. He that hath only read the Vedas, doth not know the Object knowable by them. He, however, that is established in Truth, knows the Object knowable by the Vedas. Amongst those faculties which lead to perception of the body as the acting agent, there is none by which true knowledge may be acquired. By the mind alone one cannot acquire the knowledge of Self and Not-Self. Indeed, he that knoweth Self also knoweth what is Not-self. He, on the other hand, that knoweth only what is Not-self, doth not know Truth. He, again, that knoweth the proofs, knoweth also that which is sought to be proved.