Sureśvara's Vārtika on Jyotis Brāhmaṇa

In the traditional manner of Sanskrit works, since it was necessary after BU 2.1, as an laksana portion of the Upanisad, has stated the definition of the brahman. BU 4.3 is to be understood as pariksa grantha, that is: it examines the nature of the Brahman in its pros and cons. This examination demanded detailed discussion of the theories rivalling the Vedanta prove that the Atman (viz. the Brahman) is the (internal) light of all (external) lights and reveals to one the true nature of one`s inner self and of the world of external objects which are but unreal, bringing fearlessness (abhaya) to one.