Mbh 14.26.1b

Having repaired to one teacher, and having been instructed (refined) by one word, the snakes, the deities, the Rishis, and the Danavas, all betook themselves to diverse different dispositions. It is that one who hears himself when speaking, and apprehends it duly. Once, again, is that heard from him when he speaks. There is no second preceptor.[74] It is in obedience to his counsels that action afterwards flows. The instructor, the apprehender, the hearer, and the enemy, are pleased within the heart. By acting sinfully in the world it is he that becomes a person of sinful deeds. By acting auspiciously in the world, it is he who becomes a person of auspicious deeds. It is he who becomes a person of unrestrained conduct by becoming addicted to the pleasures of sense, impelled by desire. It is he who becomes a Brahmacharin by always devoting himself to the subjugation of his senses. It is he, again, that casts off vows and actions and takes refuge on Brahman alone. By moving in the world, identifying himself the while with Brahman, he becomes a Brahmacharin. Brahman is his fuel; Brahman is his fire; Brahman is his origin; Brahman is his water; Brahman is his preceptor: he is rapt in Brahman. Brahmacharyya is even so subtle, as understood by the wise. Having understood it, they betook themselves to it, instructed by the Kshetrajna!'"'"[75]