The Advaitic formula, to be successively realized, is:- “The world is unreal; Brahman is real; the world is Brahman.+

Sage Sankara was very careful with his choice of semantic analysis and use of words - taught at different levels of doctrine at different times as the situation warranted. 

The Advaitic formula, to be successively realized, is: “The world is unreal; Brahman is real; the world is Brahman.” This is the vision of non-duality. Sage Sankara affirmed a progression of points of view depending on the stage of one’s practice.

The Advaita taught by Sage Sankara is a rigorous, absolute one. According to Sage  Sankara, whatever is, is Brahman. Brahman,  itself is absolutely homogeneous. All differences and plurality are illusory.

Sage Sankara gave out what was of most use to the greatest number of people. Therefore, in the commentaries on the Upanishads, such as the famous Mundaka, he gave the highest non-dual message of the identity of Atman and Brahman, revitalizing the philosophy and practice of Advaita, while in the commentaries on the Brahmasūtra he gave lesser teaching, positing both higher and lower Maya and higher and lower Brahman (Isvara) to explain creation for those of lesser intellects until they were ready for the highest truth.

Genuine philosophy must be independent of religion, that in Sage Sankara himself the Saguna Brahman or a personal God is only a part of the phenomenal (if not illusory) world, and the Nirguna Brahman is the only reality and has nothing to do with religion.  

Sage Sankara pokes fun at ascetics and points out that all their austerities do not cause desires to go. (Altar Flowers" Page 205, v.2 P.207 v.4)

The Brahma Sutras together with  Sage Sankara's commentary thereon do not contain the higher wisdom. They are intended for those who are incapable of thinking rationally.

Sage Sankara's commentary on the Brahma Sutras is not on a philosophical basis, but on an orthodox and mystic basis, with an appeal to the Vedas as a final authority.

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 orthodox minds, 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.  A Gnani says the scriptures for children, but wise seekers will think rationally.

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

That God created the world is an absolute lie, nevertheless one 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, dogmatism, but in the commentary Sage  Sankara cleverly introduced some philosophy. If it is objected that a number of Upanishads are equally dogmatic because they also begin by assuming Brahman, only a few Upanishads do not but prove Brahman at the end of a train of proof.

Scholars' translation of Brahma Sutras in Sacred Books of East must be read cautiously as he has not understood its highest sense, e.g. for Advaita, they wrongly put "Unity" instead of “Non-duality."

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

Orthodoxy is the home of mysticism and deification that is why they are not keen on rational truth. Thus, Sage Sankara is the Guru to the religious followers and he is a great Gnani to the seeking world.  

Sage Sankara says: ~ there is no need to study the Scriptures, in order to realize the ultimate truth or Brahman

~ then why do you indulge in studying the scriptures.

Sage Sankara says: ~ there is no need to study philosophy, in order to realize the ultimate truth or Brahman

~then why do you indulge in studying philosophy.

Sage Sankara says: ~ there is no need to indulge rituals, in order to realize the ultimate truth or Brahman

~then why do you indulge in rituals.

Sage Sankara says: ~ there is no need to indulge in yoga, in order to realize the ultimate truth or Brahman

~then why do you indulge in yoga.

Sage Sankara says the transparent Truth of the Self, which is hidden by the illusion, is to be attained through the instructions of a knower of Brahman, (Gnani)

~ then why you are sticking a Guru who is not a Gnani.

Sage Sankara says ~ “The exercise in discrimination between real and unreal and renunciation of the false is real meditation, then why you are indulging in other types of meditation.:~Santthosh Kumaar