Mundaka Upanishad:- The Para or Higher knowledge is the knowledge of the Supreme Being while the Apara or Lower Knowledge.+

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)

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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 the 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 great hindrances 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 belief, faith, creed, ritual, theological knowledge personal or opinion leads to hallucinated knowledge.  All these become a great hindrance in grasping the 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 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.  

SageSankara:~ (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, a person who engages in rituals with the notion “I am an agent, doer, thinker”, according to Sage 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), 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 innermost 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