Sage Sankara also said the study of Upanishad was neither indispensable nor a necessary prerequisite for attaining the human goal, the moksha.+

Sage Sankara strongly advocated the study of Upanishads, and at the same time cautioned that the study of Upanishads alone would not lead to moksha. In matters such as spiritual attainment, one’s own realization was the sole authority and it cannot be disputed

Sage Sankara also said the study of Upanishad was neither indispensable nor a necessary prerequisite for attaining the human goal, the moksha.

Sage Sankara pointed out; even those who were outside the Upanishad fold were as eligible for moksha as those within the fold were. He declared that all beings are Brahman, and therefore the question of discrimination did not arise. All that one was required to do was to get rid of ignorance (Avidya or duality).

Scriptures are being added from time to time by different interpreters with different interpretations. This process will go on. There is the final authority among them? One contradicts the other: duality reigns supreme. 

The scriptural citation may be quoted in pursuit of truth as authoritative only after deeper verification gets uncontradictable truth. If one quotes the scriptures without deeper verification then it is scholasticism or punditry.

The study of the Scriptures is useless to realize the ‘Self’ hidden by the dualistic illusion of Maya.

Maya or dualistic illusion is present in the form of the ‘I’. The ‘I’ is present in the form of the mind. The mind is present in the form of the universe. The universe appears as a waking or dream (duality) and disappears as deep sleep (non-duality).  Maya or illusion is product ignorance. 

Due to ignorance, the duality is experienced as reality. There is no duality in the essence of the mind. The essence is the Soul, which is present in the form of consciousness.   The consciousness alone is real and all else is unreal. Thus, consciousness is second to none. Consciousness is the ultimate truth or Brahman.

Sage Sankara indicates that scriptural studies are useless in the pursuit of truth, therefore, it is no use of indulging in scriptural studies and wasting their precious time and life.   

Even   Upanishads also confirm this:~  

Katha Upanishad: ~ This Ataman cannot be attained by the study of the Vedas, or by intelligence, nor by much hearing of sacred books. It is attained by him alone whom It chooses. To such a one Atman reveals Its own form. (Ch.-II -23-P-20)

Mundaka Upanishad:-This Ataman cannot be attained through the study of the Vedas, nor intelligence, nor through much learning. He who chooses Ataman—by him alone is Atman attained. It is Ataman that reveals to the seeker Its true nature.   (3-page -70 Upanishads Nikilanada) 

The scriptures indicate that Atman is Brahman, and Brahman is the ultimate truth. Therefore, the Soul, which is in the form of consciousness, is the ultimate truth.  

Thus, realizing the ultimate truth is the prime goal.   A well-directed inquiry, analysis, and reasoning will lead one to his non-dual destination.

The scriptures are filled just with information. By accumulating information one cannot attain wisdom.  No matter how much one knows, wisdom is not attained. One can go on gathering more and more knowledge, learn the scriptures by heart, become parrots, memorize each and every sutra or stanza, let the complete Vedas be imprinted in his memory -- but still, the wisdom will not dawn. 

Remember:~

People think that mastering scriptural knowledge is wisdom.  Pundits and religious Gurus call scriptural knowledge as wisdom. Scriptural knowledge binds one instead thus it is not liberation.  Wisdom is that which liberates one from experiencing the duality as reality.

That is why Sage Sankara, indicated in Bhaja Govindam says: ~ [Jnana Viheena Sarva Mathena Bajathi na Muktim janma Shatena] - one without knowledge does not obtain liberation even in a hundred births, no matter which religious faith he follows. 

Sage Sankara says: - VC- 58. Loud speech consisting of a shower of words, the skill in expounding the Scriptures, and likewise erudition - these merely bring on a little personal enjoyment to the scholar but are no good for Liberation.

59. The study of the Scriptures is useless so long as the highest Truth is unknown, and it is equally useless when the highest Truth has already been known.

 60. The Scriptures consisting of many words are a dense forest that merely causes the mind to ramble. Hence men of wisdom should earnestly set about knowing the true nature of the ‘Self’.

61. For one who has been bitten by the serpent of Ignorance, the only remedy is the knowledge of Brahman. Of what avail are the Vedas and (other) Scriptures, Mantras (sacred formulae), and medicines to such a one?

62. A disease does not leave off if one simply utters the name of the medicine, without taking it; (similarly) without direct realization one cannot be liberated by the mere utterance of the word Brahman.

63. Without causing the objective universe to vanish and without knowing the truth of the ‘Self’, how is one to achieve Liberation by the mere utterance of the word Brahman? — It would result merely in an effort of speech.

64. Without killing one’s enemies and possessing oneself’ of the splendor of the entire surrounding region, one cannot claim to be an emperor by merely saying, ‘I am an emperor’.

65. As a treasure hidden underground requires (for its extraction) competent instruction, excavation, the removal of stones and other such things lying above it, and (finally) grasping, but never comes out by being (merely) called out by name, so the transparent truth of the ‘Self’, which is hidden by Maya and its effects, is to be attained through the instructions of a knower of Brahman, followed by reflection, meditation and so forth, but not through perverted arguments.

66. Therefore the wise should, as in the case of disease and the like, personally strive by all the means in their power to be free from the bondage of repeated births and deaths.

Sage Sankara clearly indicated that: - yoga, intellectualism, and scriptural mastery are not the means to Self-knowledge.  But by the realization of one's identity with consciousness, which is the ultimate truth or Brahman, freedom from experiencing the illusion as reality is possible, and by no other means. 

Then there is no need for the scriptures, religion, and idea of God. One has to be more rational to realize the Advaitic truth, which is the ultimate truth or scientific truth. : ~ Santthosh Kumaar