Vedas teach Karma and Upasana to people of lower and middling intellect while Gnana is taught to those of higher intellect.+

Unless one bifurcates orthodoxy from spirituality it is impossible to acquire the Advaitic wisdom of Sage Sankara.

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 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 the 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 religious truth.  Sage Sankara declared this Advaitic truth, which is the ultimate truth to the whole world, many centuries back is the rational truth, the scientific truth, and the ultimate truth.

Thus, the Atman which is present in the form of the 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 worships 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 ignorant one (darkness) of the Soul, the innermost  Self (Atman) searches 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 religion with this concept. To call this concept 'God' would be imprecise.  The closest interpretation of the term can be found in:

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 Vedic religion, through the various yogas, is to realize that consciousness (Atman) is actually nothing but Brahman. 

Remember: ~

Mundaka Upanishad condemns rituals. The Para or Higher knowledge is the knowledge of the Supreme Being while the Apara or Lower Knowledge is that of following sacrificial rites and ceremonies. (1/2/ 1 – 6)

Physical & mental discipline such as Karma, Mantra Yoga, and Yajna, Puja Japa Blind devotion to deity or Guru is not the tool for liberation or freedom from experiencing the dualistic illusion as a reality. It is a dualistic cult including Advaitic orthodoxy propagates these disciplines. Such disciplines and codes of conduct have no value if one is seeking ultimate truth or Brahman to get Nondualistic Self-awareness. 

Mysticism, scriptural knowledge, penance based Scholasticism are the great hindrance to Self-realization. Inherited blind belief with corresponding actions based on scriptures, worship, ritual faith that imply certain mental and physical discipline, or scripture supporting the belief, faith, creed, ritual, theological knowledge personal or opinion leads to hallucinated knowledge. All these become a great hindrance to grasping, understanding, assimilating, and realizing the Advaitic or non-dual truth.

Scriptural mastery including ancient Sastras, Tarka, and Samkhya disciplines to support Karmas & belief Bhakti Argument & interpretation with the help of logic, grammar, etc.

to support beliefs, revelations, prayers, etc. In addition, dogmas, theological or other based on authorities.

That is why Sage Sankara said: -Neither by the practice of yoga nor philosophy, nor by good works nor by learning, does liberation come, but only through the realization that Atman and Brahman are one in no other way. (1) Vivekachoodamani v 56, pg~25

Sage Sankara says:~ The scriptures dealing with rituals, rewards are therefore addressed to an ignorant person.

Sage Sankara:~ (11) As regards the rituals, Sage Sankara says, the person who performs rituals and aspires for rewards will view himself in terms of the caste into which he is born, his age, the stage of his life, his standing in society, etc. In addition, he is required to perform rituals all through his life. However, the 'Self' has none of those attributes or tags. Hence, the person who superimposes all those attributes on the changeless, eternal Self and identifies Self with the body is confusing one for the other; and is, therefore, an ignorant person. The scriptures dealing with rituals, rewards, etc. are therefore addressed to an ignorant person.-Adhyasa Bhashya 

Sage Sankara:~ (11.1) This ignorance (mistaking the body for Self) brings in its wake a desire for the well-being of the body, aversion for its disease or discomfort, fear of its destruction, and thus a host of miseries(anartha). This anartha is caused by projecting karthvya(“doer” sense) and bhokthavya (object) on the Atman. Sankara calls this Adhyasa. The scriptures dealing with rituals, rewards, etc. are, therefore, he says, addressed to an ignorant person.-Adhyasa Bhashya 

Sage Sankara:~ (11.2) In short, the person who engages in rituals with the notion “I am an agent, doer, thinker”, according to Sage Sri, Sankara, is ignorant, as his behavior implies a distinct, separate doer/agent/knower; and an object that is to be done/achieved/known. That duality is avidya, an error that can be removed by Vidya.-Adhyasa Bhashya 

Sage Sankara: ~ (12) Sage Sankara affirming his belief in one eternal unchanging reality (Brahman) and the illusion of plurality, drives home the point that Upanishads deal not with rituals but with the knowledge of the Absolute (Brahma Vidya) and the Upanishads give us an insight into the essential nature of the Self which is identical with the Absolute, the Brahman.-Adhyasa Bhashya 

Sage Sankara: ~ Atman, the Self is verily Brahman (God in truth), being equanimous, quiescent, and by nature absolute Existence, Knowledge, and Bliss. Atman is not the body that is non-existence itself. This is called true Knowledge by the wise.

Everyone’s inner work is on. The Soul is the Self. The Soul the inner Guru guides us all till we get the stillness of its Advaitic true nature. It is the Soul that is in ignorance it is the Soul that has to wake from the sleep of ignorance. : ~Santthosh Kumaar