Atman is Brahman or God in truth, the One without a Second.+

Atman is Brahman or God, the One without a Second.

The Atman is Self-evident. It is not established by extraneous proofs. It is not possible to deny the Atman, because It is the very essence of the one who denies It. The Atman is the basis of all kinds of knowledge, presuppositions, and proofs.

The Soul, is present in the form of consciousness, is real and eternal. The world in which we exist is an illusion created out of consciousness.

Rig Veda: ~ The Atman (Soul or Spirit) is the cause; Atman is the support of all that exists in this universe. May ye never turn away from the Atman, the ‘Self’. May ye never accept another God in place of the Atman nor worship other than the Atman?" (10:48, 5)

Brihadaranyaka Upanishad: ~ Brahman (God in truth) is in the form of the Athma, and it is indeed Athma itself’.

Sage Sankara’s Supreme Brahman (God) is impersonal, Nirguna (without Gunas or attributes), Nirakara (formless), Nirvisesha (without special characteristics), immutable, eternal and Akarta (non-agent). It is above all needs and desires. It is always the Witnessing Subject. It can never become an object as it is beyond the reach of the senses. Brahman is non-dual, one without a second. It has no other beside it. It is destitute of difference, either external or internal. Brahman cannot be described, because description implies a distinction. Brahman cannot be distinguished from any other than It. In Brahman, there is not a distinction between substance and attribute. Sat-Chit-Ananda constitutes the very essence or Svarupa of Brahman, and not just its attributes. The Nirguna Brahman of Sage  Sankara is impersonal

Thus, it refers to formless and attributeless God, which is the Atman (Soul), the innermost ‘Self’ within the false experience. Thus it indicates clearly all the Gods with form and attributes are mere imagination based on the false ‘Self’.  Thus Atman or Soul, the innermost ‘Self’ is God.

Sage Sankara wanted to establish the existence of the Brahman. For this purpose, He made the Atman as the Brahman. He brought out the identity of Self with the consciousness and made the Atman the Brahman. Since one will not negate the existence of his Self, he will accept the existence of the Brahman, which is the Atman or Soul the innermost Self. Both Bhagavan Buddha and Sage Sankara kept silent about the absolute unimaginable God. The same philosophy was dealt with by them in different angles in different situations.

Sage  Sankara not only proved the existence of God on the Vedic perspective but also proved the existence of God rationally by pure reason.

Sage Sankara himself had often said that his philosophy was based on Sruti or revealed scripture.  This may be, because, Sage Sankara addressed the ordinary man, who finds security in the idea of causality and thus, in the idea of God—and Revelation is indispensable to prove the latter.  He believed that those of superior intelligence, have no need of this idea of divine causality, and can, therefore, dispense with Sruti and arrive at the truth of Non-Dualism by pure reason.

Remember:~

Dualist gurus say: ~ God cannot exist without attributes. Then they are making God as an object whereas God is the subject. Attributes can only be seen in an objective world. Causality appears in the duality, but when one goes deeper into the matter even there the causality disappears.

Then they are making God as an object whereas God is the subject. Attributes can only be seen in an objective world. Causality appears in the duality, but when one goes deeper into the matter even there the causality disappears.

The Gods with forms and attributes exist only in the domain of the form, time and space.

Advaitic God is (Brahman) is Nirguna without the form and attributes. 

Sage Sankara: ~

Brahman (God in truth) is impersonal

Nirguna (without Gunas or attributes)

Nirakara (formless)

Nirvisesha (without special characteristics)

Immutable, eternal and Akarta (non-agent)

It is above all needs and desires. It is always the Witnessing Subject. It can never become an object as it is beyond the reach of the senses.

 Brahman (God in truth) is non-dual, one without a second.

It has no other beside it.

It is destitute of difference, either external or internal. Brahman cannot be described because the description implies a distinction.

Brahman cannot be distinguished from any other than it.

In Brahman, there is not a distinction between substance and attribute.

Awareness is the very nature of Brahman (God in truth).

The Gods with forms and attributes exist only in the domain of form, time and space. : ~ Santthosh Kumaar