Bhagavad Gita Chapter 11 Verse 18
भगवद् गीता अध्याय 11 श्लोक 18

त्वमक्षरं परमं वेदितव्यं
त्वमस्य विश्वस्य परं निधानम्।
त्वमव्ययः शाश्वतधर्मगोप्ता
सनातनस्त्वं पुरुषो मतो मे।।11.18।।



हिंदी अनुवाद - स्वामी तेजोमयानंद
।।11.18।। आप ही जानने योग्य (वेदितव्यम्) परम अक्षर हैं आप ही इस विश्व के परम आश्रय (निधान) हैं आप ही शाश्वत धर्म के रक्षक हैं और आप ही सनातन पुरुष हैं?ऐसा मेरा मत है।।


Kumara Vaishnava Sampradaya - Commentary
The Vedic scriptures known as the Upanisads declare also that  Lord  Krishna
is aksaram paramam the Supreme immutable ultimate reality  and  declared  in
the Vedic scriptures as that which  is  essential  to  be  known.  The  word
veditavyam means He is only to be know by  the  absolute  authority  of  the
Vedas. The word avyayah means that which is imperishable and  can  never  be
diminished for in whatever aspect or  form  or  manifestation  Lord  Krishna
wills to be that will eternally  be  existing.  The  phrase  sasvata-dharma-
gopta means the Supreme Lord Krishna is the  eternal  preserver  of  eternal
righteousness embodied in the Vedic scriptures. This is done by Himself  and
by His authorised avatars o  incarnations  and  expansions  as  revealed  in
Vedic scriptures such as Narayana, Rama, Vishnu, Narasimhadeva, Buddha  etc.
The words sanatanas tvam puruso means Lord Krishna  is  the  eternal  spirit
and primal consciousness of  all  creation  as  affirmed  in  the  Taittriya
Upanisad III.XII beginning vedaham  etam  purusam  meaning  I  perceive  the
magnificent Purusa. Also in the Mundaka Upanisad I.I.IV beginning dve  vidye
veditavye meaning: The Purusa is more sublime than  the  most  sublime.  All
this is as the  ornament  of  the  complete  cosmic  creation  Lord  Krishna
exhibited His visvarupa or divine universal form and is understood as such.