1. When we look at the passage on AUM in the Prashna Upanishad we see that though these utterances may seem perplexing to our rational mind, they cannot be dismissed as childish mysticism. These are imaged expressions natural to the mentality of the Vedantic time. Our reason itself by its own processes is now showing these teachings to be true and are a profound truth and real reality of knowledge.
2. The metrical Upanishads continue this symbolism but pass beyond this kind of image to the overt expression.
3. The Self, Spirit, the Godhead in man and creatures and Nature and all this world and other worlds and beyond all cosmos, the Immortal, the One, the Infinite is hymned without veils in the splendor of his eternal transcendence and his manifold self-revelation.
4. A few passages from the teaching of Yama, Lord of Death to Nachiketas will be enough to illustrate it:
“Om is the syllable. This syllable is the Brahman and the Supreme. He who knows OM, whatsoever he wills, it is his. The support of OM is the highest and best and heightens man into the world of Brahman. The Omniscient is not born, nor dies, nor is he anyone. He is unborn, constant and eternal.
The wise man comes to know that the great Lord and Self established and bodiless in these bodies that pass and has no longer any grief.
The Self is to be won not by teaching nor by brain-power nor learning. He whom the Spirit chooses, by him alone it can be won, and to him this Spirit discloses its own very body.
One who has not ceased from ill-doing, one who is not concentrated and calm, one whose mind is not tranquil, shall not get the Spirit by the brain’s wisdom.”