Bhagavad Gita Chapter 13.18
jyotiṣām api taj jyotis
tamasaḥ param ucyate
jñānaḿ jñeyaḿ jñāna-gamyaḿ
hṛdi sarvasya viṣṭhitam
Translation
He is the source of light in all luminous objects. He is beyond the darkness of matter and is unmanifested. He is knowledge, He is the object of knowledge, and He is the goal of knowledge. He is situated in everyone’s heart.