Mundaka Upanishads: ~ So-called spiritual pundits and learned are called children because a child takes whatever it thinks as truth. The question never occurs to children “Is what I have seen or thought really the truth?" (P.334 line 9)
Advaitic wisdom does not need the support of any Scripture or Revelation like the Veda. For it is based, not upon the varying theological fancies, which are as numerous as the sands of the sea, but upon reason, the common heritage of all mankind, irrespective of colour or creed or clime.
Vedanta it is that Lord teaches us in the Gita and in it, he lashes out against the karmakanda. It is generally believed that the Buddha and Mahavira were the first to attack the Vedas.
It is not so. Lord Sri Krishna himself spoke against them long before these two religious leaders. At one place in the Gita he says to Arjuna:~ "The Vedas are associated with the three qualities of sattva, rajas and tamas.
You must transcend these three qualities. Full of desire, they (the practitioners of Vedic rituals) long for paradise and keep thinking of pleasures and material prosperity. They are born again and again and their minds are never fixed in Samadhi, these men clinging to Vedic rituals.
“In another passage Krishna declares :~ "Not by the Vedas is Self to be realised, nor by sacrifices nor by much study.
Bhagavad Gita 2:46:~ "A man of true knowledge who has attained enlightenment, has the same use for all the scriptures as one has for a small reservoir of water in a place flooded on all sides."
Katha Upanishad: ~ This Atman cannot be attained by the study of the Vedas, or by intelligence, or 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 Atman cannot be attained through study of the Vedas, nor through intelligence, nor through much learning. He who chooses Atman—by him alone is Atman attained. It is Atman that reveals to the seeker Its true nature. (3 –page-70
Sage Sri, Sankara: ~ VC- Let erudite scholars quote all the scripture, let Gods be invoked through sacrifices, let elaborate rituals be performed, let personal Gods be propitiated---yet, without the realization of one‘s identity With the Self, there shall be no liberation for the individual, not even in the lifetimes of a hundred Brahmas put together (verses-6)
In spirituality, the ultimate truth is God. The Atman is the ultimate truth or Brahman or God.
Sage Sri, Sankara says: ~ The scriptures dealing with rituals, rewards are therefore addressed to an ignorant person.