A form of meditation is called upadesha. The pupil goes to a teacher who leads him to the highest form of knowledge. However, mere analysis or listening to the guru is not enough to attain the knowledge of Brahman. Upanishads insist that the teachings be supplemented by meditation. The highest form of meditation is said to be concentration on the truth aham brahmasmi – I am Brahman. This is the absolute Brahman which is one with our inner self. One has to learn this kind of meditation from the right guru. Upanishads give various hints regarding the methods of meditation. Hence, guru’s guidance is very important, for without him we still remain ignorant.
Upanishads, however, declare that the heart of man is the sanctuary wherein the Supreme Brahman dwells. As aids to meditation, the Upanishads have accepted various objects as symbols of Brahman and, of these, the mystic syllable om is considered the most important.
As per Chandogya Upanishad, upasana is intense meditation done with a single focus until the upasaka or the practitioner becomes one with the upasya or the object of focus.
In Chandogya Upanishad, there is a dialogue between Uddalaka and his son, Svetaketu. This dialogue throws great light on the saying tat tvam asi. In the dialogue between Uddalaka and his son Svetaketu, one can learn that which is the subtle essence, in that is all this existence, and that which is sat – existence itself – that thou art. This is the fundamental truth of the philosophy of Upanishads – the identity between Brahman and atman, between God and man.
Chapter VII of Chandogya Upanishad, known as Prajapati Vidya, narrates a story.
Indra, from the devas or gods, and Virochana, from the asuras or demons, approached Prajapati (a teacher) and after having served him for 32 years begged him to teach them the knowledge of the self.
Prajapati wanted to explain to Indra that the mind is not the self, because the self continues to exist without the mind. He asked Indra to analyze the state of deep sleep. Indra, who had identified the mind with the self, discovered that he had not know the self because in a state of dreamless sleep the mind is almost annihilated. Hence Indra was dissatisfied with the answer and wished to pursue further. He approached Prajapati again, who then revealed to him the highest truth of the self. The guru explained to the pupil that the body is mortal and can die. But in that physical body lies the immortal self, which is formless. As long as one is conscious of the body, one is subject pain, pleasure and suffering. The minute one rises above physical consciousness, knowing the self as distinct from the senses, sense-organs and the mind, knowing him in this true light, one rejoices and is free. He who knows that self, and meditates and realizes that self, obtains all worlds and all desires. Here one becomes one with God, and freedom comes with the knowledge of this true self. As man is ignorant of this self, he considers himself finite, bound and miserable. Man can recognize his own divine self and the ultimate truth.
In this regard, Chandogya Upanishad says that the search for Brahman within oneself is like the search for hidden treasure underground. One walks over it again and again and yet never finds it. Similarly, although Brahman is within the human being, he never finds him because a covering of ignorance hides him. Of the Brahman, the Upanishad says that Brahman is the self within, untouched by any deed, ageless and deathless, free from hunger, grief and thirst. The etheric center within the heart, where the Brahman dwells, is like a boundary that separates That from the mundane world. Day and night do cross that boundary. Nothing can touch Brahman – neither old age, nor death; neither grief, nor pleasure, nor good, nor wrong deeds. All inauspicious shuns that, because that is free and can never be touched by an impunity.