'pranava, maha-vakya--taha kari' acchadana
mahavakye kari 'tat tvam asi'ra sthapana
pranava—omkara; maha-vakya—principal mantra; taha—that; kari'-making; acchadana—covered; maha-vakye—in place of the principal mantra; kari—I do; 'tat tvam asi'ra sthapana—establishment of the statement tat tvam asi.
"Pranava [omkara] is the maha-vakya [maha-mantra] in the Vedas. Sankaracarya's followers cover this to stress without authority the mantra tat tvam asi.
The Mayavadi philosophers stress the statements tat tvam asi, so 'ham, etc., but they do not stress the real maha-mantra, pranava (omkara). Therefore, because they misrepresent Vedic knowledge, they are the greatest offenders to the lotus feet of the Lord. Caitanya Mahaprabhu says clearly, mayavadi krsne aparadhi: "Mayavadi philosophers are the greatest offenders to Lord Krsna." Lord Krsna declares:
tan aham dvisatah kruran
ksipamy ajasram asubhan
asurisv eva yonisu
"Those who are envious and mischievous, who are the lowest among mankind, I perpetually cast into the ocean of material existence, into various demoniac species of life." (Bg. 16.19) Life in demoniac species awaits the Mayavadi philosophers after death because they are envious of Krsna. When Krsna says in the Bhagavad-gita (9.34), man-mana bhava mad-bhakto mad-yaji mam namaskuru ("Engage your mind always in thinking of Me, become My devotee, offer obeisances to Me and worship Me"), one demoniac scholar says that it is not Krsna to whom one must surrender. This scholar is already suffering in this life, and he will have to suffer again in the next if in this life he does not complete his prescribed suffering. One should be very careful not to be envious of the Supreme Personality of Godhead. In the next verse, therefore, Sri Caitanya Mahaprabhu clearly states the purpose of the Vedas.
Link to this page: https://prabhupadabooks.com/cc/adi/7/130