The author had quoted from this Upanishad and explained its ideas in several of his lectures, class-talks, and conversations. All this material, spread throughout the nine volumes of his Complete Works, has been brought together in this book for the first time. What makes this compilation a treasure trove of original ideas and masterly insights is that the author goes straight to the heart of the subject to focus on the essentials, and to evolve practical methods from abstract principles.
Tremendous purity, tremendous renunciation, is the one secret of spirituality. Neither through wealth, nor through progeny, but through renunciation alone is immortality to be reached, say the Vedas. Sell all that thou hast and give to poor, and follow me, says the Christ. So all great saints and prophets have expressed it, and have carried it out in their lives. How can great spirituality come without renunciation? - Swami Vivekananda