Sage Sankara‘s doctrines spread after his lifetime. Very few were capable of understanding his wisdom.+

India is the home of mysticism and deification and very few are keen on rational Advaitic truth.

Sage Sankara gave religion and scholasticism and yoga no less than philosophy, to the world. He was great enough to be able to do so.  His commentary on Manduka Upanishads is pure philosophy, but many of his other books are presented from a religious standpoint to help those who cannot rise up to philosophy.

In Brahma Sutra Sage Sankara takes the position that there is another entity outside us, i.e. the wall really exists separately from the mind. This was because Sage Sankara explains in Manduka that those who study the Sutras are religious minds, and intellectual children, hence his popular viewpoint to assist them. These people are afraid to go deeper because it means being heroic enough to refuse to accept Sruti, and God's authority, in case they mean punishment by God.

Sage Sankara says: Keep the scriptures for children but throw them on the fire for wise seekers.

In Brahma Sutras Sage Sankara takes for granted, and assumes that a world was created: He there mixes dogmatic theology with philosophy.

That God created the world is an absolute lie; nevertheless, you will find Sage  Sankara (in his commentary on Vedanta Sutras) clearly says this! He has to adapt his teachings to his audience, reserving the highest for philosophical minds.

The text of Brahma Sutras is based on religion and dogmatism, but in the commentary Sankara cleverly introduced some philosophy. If it is objected that a number of Upanishads are equally dogmatic because they also begin by assuming Brahman, but a few Upanishads do not but prove Brahman at the end of a train of proof.

The causality and creation, but are for religious people only.  Religion is only for those who are unable to understand the truth beyond form, time, and space. Religion is not final. It only gives satisfaction to the populace. The Self - knowledge is for the whole of humanity to free them from experiencing birth, life, death, and the world as reality.

People of small intelligence follow religion and believe that the world was created by God. But how do they know that He did so? When a pot is created, one can see both pot and its maker, but not in the case of the world.

Sage Sankara‘s doctrines spread after his lifetime.  Very few were capable of understanding his wisdom.  The orthodox pundit’s followers are not Gnanis or have grasped the Advaitic wisdom.

Sage Sankara varied his practical advice and doctrinal teaching according to the people he was amongst. He never told them to give up their particular religion or beliefs or metaphysics completely; he only told them to give up the worst features of abuse: at the same time he showed just one step forward toward the truth.  The followers of Sage  Sankara have constituted a religious sect. Thus, all movements ultimately degenerate.

According to Sage Sankara Orthodoxy which is stuck to the ritualistic pursuit is meant for the ignorant populace.   The seeker of truth has to discard the orthodox baggage.  The Secker of truth must thirst for Sage Sankara’s wisdom is all that matters. Sage  Sankara says:~ One must first know what is before him. If he cannot know that, what else can he know or understand? If he gives up the external world in his inquiry, he cannot get the whole truth.

Sage Sankara's work has got two aspects: the dualistic perspective and the nondualistic perspective.

Sage Sankara gave religious, ritual, and dogmatic instruction to the populace but the Advaitic wisdom only to the few who could rise to it. Hence the interpretation of his writings by commentators is often confusing because they mix up the two viewpoints. Thus, they may assert that ritual is a means of realizing Brahman, which is absurd.

Sage Sankara taught that it was only through direct knowledge of Advaita that one could be enlightened.

Sage Sankara’s critics accused him of teaching Buddhism in the garb of Santana Dharma because his non-dualistic ideals were a bit radical to contemporary Vedic philosophy. However, it may be noted that while the Later Buddhists arrived at a changeless, deathless, absolute truth after their insightful understanding of the unreality of samsara, historically Vedantins never liked this idea.

Although Advaita also proposes the theory of Maya, explaining the universe as a "trick of a magician", Sage Sankara and his followers see this as a consequence of their basic premise that Atman is real. Their idea of Maya emerges from their belief in the reality of Atman, rather than the other way around.

Sage  Sankara was a peripatetic orthodox monk who traveled the length and breadth of India. The more enthusiastic followers of the Advaita tradition claim that he was chiefly responsible for "driving the Buddhists away". Historically the decline of Buddhism in India is known to have taken place long after Sage Sankara or even Kumarila Bhatta (who according to a legend had "driven the Buddhists away" by defeating them in debates), sometime before the Muslim invasion into Afghanistan (earlier Gandhara).

Although today's followers of Advaita believe Sage Sankara argued against Buddhists in person, a historical source, the Madhaviya Sankara Vijayam, indicates that Sage  Sankara sought debates with Mimamsa, Samkhya, Nyaya, Vaisheshika, and Yoga scholars as keenly as with any Buddhists. In fact, his arguments against the Buddhists are quite mild in the Upanishad Bhashyas, while they border on the acrimonious in the Brahma Sutra Bhashya.

The Visishtadvaita and Dvaita schools believe in an ultimate attribute Atman. They differ passionately with Advaita and believe that his attriubuteless Atman is not different from the Buddhist Shunyata (nothingness ness) ~ much to the dismay of the Advaita School. A careful study of the Buddhist Shunyata will show that it is in some ways metaphysically similar to Atman. Whether Sage Sankara agrees with the Buddhists is not very clear from his commentaries on the Upanishads. His arguments against Buddhism in the Brahma Sutra Bhashya are more a representation of Vedantic traditional debate with Buddhists than a true representation of his own individual belief.

Chandogya Upanishad: ~   Sarvam khalvidam brahma ~ all this (universe) is verily Brahman. By following back all of the relative appearances in the world, we eventually return to that from which it is all manifest – the non-dual reality. 

Sage Sankara’s Supreme Brahman (God) is impersonal, Nirguna (without Gunas or attributes), Nirakara (formless), Nirvisesha (without special characteristics), immutable, eternal, and Akarta (non-agent). It is above all needs and desires. It is always the Witnessing Subject. It can never become an object as it is beyond the reach of the senses. Brahman is non-dual, one without a second. It has no other besides it. It is destitute of difference, either external or internal. Brahman cannot be described, because description implies a distinction. Brahman cannot be distinguished from any other than It. In Brahman, there is not a distinction between substance and attribute. Sat-Chit-Ananda constitutes the very essence or Svarupa of Brahman, and not just Its attributes. The Nirguna Brahman of Sage Sankara is impersonal.

Sage Sankara: ~"That which permeates all, which nothing transcends and which, like the universal space around us, fills everything completely from within and without, that Supreme non-dual Brahman  (God)."

Thus, truth-realization is Self-realization. Self-realization is God-realization.  God-realization itself is real worship. :~Santthosh Kumaar