ॐतत्सदिति निर्देशो ब्रह्मणस्त्रिविधः स्मृतः | ब्राह्मणास्तेन वेदाश्च यज्ञाश्च विहिताः पुरा
OMtatsaditi nirdeśo brahmaṇastrividhaḥ smṛtaḥ . brāhmaṇāstena vedāśca yajñāśca vihitāḥ purā
‘Om-tat-sat’ [‘Om, That, Existence’: ‘Om iti brahma, Om is Brahman’ (Tai. 1.8.1); ‘Tattvamasi, Thou art That’ (Ch. 6.8.7); and ‘Sadeva somya idamagra asit, This was Existence alone in the beginning, O amiable one’ (Ch. 6.2.1)-in these texts Brahman is indicated by the words Om, tat, sat.]-this is considered to be the threefold designation of Brahman. The Brahmanas and Vedas and the sacrifices were ordanined by that in the days of yore.
‘ऊँ, तत् सत्’ ऐसा यह ब्रह्म का त्रिविध निर्देश (नाम) कहा गया है; उसी से आदिकाल में (पुरा) ब्राहम्ण, वेद और यज्ञ निर्मित हुए हैं।।