The Bhagavad Gita with Commentaries of Ramanuja, Madhva, Shankara and Others.
Bhagavad Gita 8.20
http://www.bhagavad-gita.us/articles/346/1/Bhagavad-Gita-820/Page1.html
By Bhagavan Sri Krishna
 

Text 20

paras tasmat tu bhavo ’nyo
’vyakto ’vyaktat sanatanah
yah sa sarveshu bhutesu
nasyatsu na vinasyati

Translation

Yet there is another unmanifest nature, which is eternal and is transcendental to this manifested and unmanifested matter. It is supreme and is never annihilated. When all in this world is annihilated, that part remains as it is.

Commentary by Srila Prabhupada

rishna’s superior, spiritual energy is transcendental and eternal. It is beyond all the changes of material nature, which is manifest and annihilated during the days and nights of Brahma. Krishna’s superior energy is completely opposite in quality to material nature. Superior and inferior nature are explained in the Seventh Chapter.

Commentary by Sri Visvanatha Cakravarti Thakur

Superior to that state of dissolution, to the Hiranyagarbha or Brahma which has been described (parah tasmat avyaktat), is another state,  the cause  of Hiranyagarbha, which is indeed unmanifest (avyakta), and without beginning (sanatanah).