etad vai tat – This verily is that ! - Mananam from Katha Upanisad (12 verses).
222 aum namO bhagavathey vaivasvathAya mruthyave brahmavidyAchArya nachiketase cha. Salutation to Bhagavan Yama (death), son of the Sun (vivasvAn) and the imparter of Brahma Vidya to Nachiketa. The following 12 verses have the constant refrain etad vai tat – This verily is that , reminding us our essential nature, while guiding us to recognize our Self as it really is. Why does Sruti repeat the truth 12 times ? Sri Sankara while commenting on Katha 2.2.8 says : - QUOTE The knowledge of the unity of the Self is supported by pramAna and is reiterated quite often, yet it does not stick in the minds of those with crooked intellect, i.e. in the minds which have become unsettled on account of the (consuming varied) views of numerous logicians. Therefore, Sruti, with the anxiety for (thier well being & proper knowledge ) inculcation, says (the truth - etad vai tat) again and again.... UNQUOTE -------------------- yena rūpa ṃ rasa ṃ gandha ṃ śabdān sparśāg ͫ ś ca maithun ā n .