Tattireya Upanishad (II.1):~ where Brahman is described in the following manner: Satyam Jnanam Anantam Brahman.+

Sage Goudpada says that: ~ The merciful Veda teaches Karma and Upasana to people of lower and middling intellect, while jnana is taught to those of higher intellect.

So he clearly indicates that rituals and theories are not meant for those who are searching for higher knowledge or wisdom.

Ish Upanishads: ~ Vidya and Avidya both are hindrances to Self-knowledge, but Vidya is even worse than Avidya. The word Vidya is used here in a special sense; here it means worshipping Gods and Goddesses. By worshipping Gods and Goddesses, you will go after death to the world of Gods and Goddesses. But will that help you? The time you spend there is wasted because if you were not there, you could have spent that time moving forward towards Self-knowledge, which is your goal. In the world of Gods and Goddesses, you cannot do that, and thus you go deeper and deeper into darkness.

Avidya is Karma and therefore, a hindrance. You perform Avidya - i.e., you perform Agnihotra and other sacrifices. This is a roundabout way of purifying the mind, and it is also groping in the dark. But it may not have as heavy a toll on your time and energy as the other.

Sage Sankara says: ~ Atman is Brahman. The Atman alone is real is not the religious truth. Sage Sankara declared this Advaitic truth, which is the ultimate truth to the whole world, many centuries back, to be the rational truth, the scientific truth, and the ultimate truth.

Thus, the Atman, which is present in the form of consciousness, is real and eternal; the world in which we exist is merely an illusion.

Ishopanishad "They are steeped in ignorance and sunk into the greatest depth of misery who worship the matter, instead of the All-Pervading God, and those who worship things born of matter like trees, animals, man, etc., are sunk deeper in misery."

Katha Upanishad says: ~Fools dwelling in darkness, but thinking themselves wise and erudite, go round and round, by various tortuous paths, like the blind led by the blind. (Ch II-5 P-14 Upanishads Nikhilananda)

It indicates that the one who is ignorant (darkness) of the Soul, the innermost Self (Atman), searches for truth by accumulating knowledge of every path and practice, and is uncertain about the truth, and thinks every path leads towards reality. The ignorance of the true Self leads one towards unreality or hallucination.

Bhad Upanishad: ~ This Self is dearer than a son, dearer than wealth, dearer than everything else because It is innermost. If one holding the Self dear were to say to a person who speaks of anything other than the Self as dear, that he, the latter, will lose what he holds dear—and the former is certainly competent to do so—it will indeed come true. One should meditate upon the Self alone as dear. He who meditates upon the Self alone as dear, what he holds dear will not perish. ((8-p- -211)

It is the first instance of monism in organized religion. Vedic religion remains the only major religion to incorporate this concept. To call this concept 'God' would be imprecise. The closest interpretation of the term can be found in the:~

Tattireya Upanishad (II.1):~ where Brahman is described in the following manner: Satyam Jnanam Anantam Brahman - "Brahman is of the nature of truth, knowledge, and infinity". Thus, Brahman is the origin and the end of all things, material or otherwise. Brahman is the root source and Divine Ground of everything that exists and does not exist. It is defined as unknowable and Satchidananda (Truth-Consciousness-Bliss).

Since it is eternal and infinite, it comprises the only truth. The goal of the Vedic religion, through the various yogas, is to realize that the consciousness (Atman) is actually nothing but Brahman. : ~ Santthosh Kumaar