Bhagavad Gita · Chapter 13: The Field and the Knower of the Field
Bhagavad Gita 13.32
यथा सर्वगतं सौक्ष्म्यादाकाशं नोपलिप्यते ।
सर्वत्रावस्थितो देहे तथात्मा नोपलिप्यते ॥
yathā sarvagataṃ saukṣmyādākāśaṃ nopalipyate | sarvatrāvasthito dehe tathātmā nopalipyate ||
As space, which is everywhere, is not stained because it is so subtle, so the self, present everywhere in the body, is not stained.
Modern context
Space is everywhere, yet nothing in it stains it. Smoke passes through it, mud is thrown through it, yet space itself is not dirtied. The self is like that: present in every part of the body, yet untouched by anything the body does. The image is simple and powerful. Whatever passes through the space of awareness, awareness itself remains clear.