Self-knowledge or Brahma Gnana or Atma Gnana is Adyatma.+

Adyatma is knowledge of Brahman or God, which is beyond form, time, and space.

Self-knowledge or Brahma Gnana or Atma Gnana is Adyatma.

Adyatma is nothing to do with religious sects or creeds and religious beliefs. 

Adyatma is pure spirituality. 

Knowledge of Atma is Adyatma. 

Advaita is Adyatma.

Adyatma is the knowledge of the truth beyond form, time, and space. 

bifurcate religion, yoga, and theoretical philosophy and based the truth on the Atma it is Adyatma.

Adyatma is based on the ultimate truth which is based on the Atma or Spirit, which is the innermost Self.

Vedas are of the Adyatma because Vedas are based on the Atma the supreme Spirit. 

Rig Veda: ~ 'Prajnanam Brahma'- Consciousness is the ultimate reality or Brahman or God in truth.

Do not accept any other truth other than consciousness. Consciousness is the ultimate truth. Nothing is real but consciousness. Realize consciousness as the ultimate truth or Brahman or God in truth. Consciousness is everywhere and in everything. Let these words be inscribed in your subconscious.

Yajurveda – chapter- 32:~ God is  Supreme Spirit.

Vedas confirm the  Atma (Soul), the innermost Self, is present in the form of the Spirit or the consciousness is the ultimate truth or  Brahman or  God in truth. 

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 innermost self. May ye never accept another God in place of the Atman nor worship other than the Atman?" (10:48, 5) 

The Spirit is the root element of the universe. The Spirit is present in the form of the Soul, the Self. The Soul is present in the form of consciousness. 

From the Spirit, the universe comes into existence. In the Spirit, the universe resides. And into the Spirit, the universe is dissolved. The Spirit is the parent of all that is there is. 

In Yajurveda says: ~ 

Translation 1.

They enter darkness, those who worship natural things (for example air, water, sun, moon, animals, fire, stone, etc).

They sink deeper in darkness those who worship sambhuti. (Sambhuti means created things, for example, table, chair, idol, etc.) (Yajurveda 40:9)

Translation 2.

"Deep into the shade of blinding gloom fall asambhuti's worshippers. They sink to darkness deeper yet who on sambhuti are intent." (Yajurveda Samhita by Ralph T. H. Giffith pg 538)

Translation 3.

"They are enveloped in darkness, in other words, are steeped in ignorance and sunk in the greatest depths of misery who worship the uncreated, eternal prakrti -- the material cause of the world -- in place of the All-pervading God, But those who worship visible things born of the prakrti, such as the earth, trees, bodies (human and the like) in place of God are enveloped in still greater darkness, in other words, they are extremely foolish, fall into an awful hell of pain and sorrow, and suffer terribly for a long time." (Yajur Veda 40:9.)

So, Yajur Veda indicates that: ~

They sink deeper in darkness those who worship sambhuti. (Sambhuti means created things, for example, table, chair, idol, etc (Yajurved 40:9)

Those who worship visible things born of the prakrti, such as the earth, trees, bodies (human and the like) in place of God are enveloped in still greater darkness, in other words, they are extremely foolish, fall into an awful hell of pain and sorrow, and suffer terribly for a long time." (Yajur Veda 40:9.)

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

There is a clear-cut idea of God in the Vedas, Upanishad, and Bhagavad Gita. And also there is a clear-cut idea of what not to worship as God in place of real God. 

Bhagavad Gita: ~ Brahmano hi pratisthaham ~ Brahman (God) is considered the all-pervading consciousness, which is the basis of all the animate and inanimate entities and material. (14.27). 

When Bhagavad Gita says, God is considered the all-pervading consciousness which is the basis of all the animate and inanimate entities and material then nothing has to be accepted as God other than consciousness. 

Lord Krishna says Ch ~V: ~ “Those who know the Self in truth.". The last two words (tattvataha) are usually ignored by pundits, but they make all the difference between the ordinary concept of God and the truth about God. 

That is why Sage Sankara said:~ Talk as much philosophy as you like, worship as many Gods as you please, observe ceremonies, and sing devotional hymns, but liberation will never come, even after a hundred aeons, without realizing the Oneness.

The religion of the Veda knows no idols, then why so many Gods and Goddesses with different forms and names are being propagated as Vedic Gods. Why these conceptual Gods are introduced when the Vedic concept of God is free from form and attributes.

As one peeps into the annals of the Indian religious history he finds that some saints in the past introduced the concept of God with attributes.

Remember:~

Yajur Veda says:~   those who worship visible things, born of the prakrti, such as the earth, trees, bodies (human and the like), in place of God are enveloped in still greater darkness. Therefore, all these adulterated add-ons prove that the form and attribute-based concepts are introduced by some sages of the past with a new belief system and code of conduct in the name of Vedas. 

Sruti is made the final or exclusive authority in apara Vidya and that for supporting the tenet of the causal relation or creatorship of Brahman, Nirguna Brahman = the "Absolute beyond qualities," which can be defined only in a negative way.

For the Sankarian school = the Ultimate Reality, higher than the Lord. i.e. of Saguna or apara Brahman ... The support of Scriptural Revelation is, therefore, absolutely necessary for this hypothesis of cosmology, this Saguna or apara (= inferior) Brahman, but not for the absolute truth of Nirguna Brahman. 

The Sruti itself’ says:~  "This Atma is NOT to be attained by a study of the Vedas.  (Katha Upanishad I, 2, 23.)   

        

Therefore, all the adulterated add-ons and attribute-based knowledge, which are inferior, have to be bifurcated and excluded to know the ultimate truth.  The seeker of truth has to drop all the inferior knowledge based on the attributes and go beyond the Vedas to understand assimilate and realize the ultimate truth or Brahman. 

One has to go beyond Vedas means to go beyond religion. Going beyond religion means, going beyond   God based on blind faith or blind belief.  Going beyond the Vedas, the Religion, and the belief God is going beyond the illusion.   That is the end of the Vedas (Veda –antha).  The realization of the ultimate truth or Brahman or  God in truth is Adyatma.:~Santthosh Kumaar