In Chapter 3 of Part II of Sri Brhad-bhagavatamrta, in the Dig Darsani of Sanatana Goswami, the reason for the appearance of Sankaracarya is given: Lord Krsna says to Lord Siva, ‘ “By concocting your own doctrines, turn the general populace against Me.” Because Sri Krsna wanted to keep His pure devotional service confidential, He requested Lord Siva to create this confusion. But Vaisnavas whose only serious ambition in life is to achieve the blissful rasa of worshiping Krsna reject impersonal liberation. Gopa-kumara, Lord Siva advises, should reject it also, like any obstacle to his practice of bhagavad-bhakti.’ In the Sri Tattva Sandharbha of Jiva Goswami, Sankara’s mission for the Lord is detailed as follows: “…the people were not prepared to hear seriously about the personality of the Supreme Lord, His transcendental, eternal, blissful form, or His variegated abode. They would have simply blasphemed these teachings, and then they would have been left with no way to purify their hearts. So the first task in bridging the wide gap between voidism and personalism was to reawaken people’s faith in the vedas. It was for this purpose that Sankaracarya introduced Advaita-vada, a version of monism in between voidism and personalism.”
Why Sankara?