18.63 Iti te etc. : The [path of] wisdom has been taught to you.  It is a better secret than the secret literature i.e.,  the last portion of the Vedas  (the Upanisads), as it reveals the supreme Non-duality  (Advaita-philosophy).  Comprehend it fully and then :  Deliberate on the purport of it and then.				
 The purport has been, no doubt, elucidated by us by taking-by-horn-method  (directly)  whenever occasion arose.  Yet, a clear reflection of the entire subject matter is shown here.  Because it is the choicest one, the mind is never satisfied, when it is being elucidated and listened to.  The most secret thing is being determined here. The method by which that is known, you must listen to now - so He says :-