Bhagavad Gita 13.32
यथा सर्वगतं सौक्ष्म्यादाकाशं नोपलिप्यते। सर्वत्रावस्थितो देहे तथात्मा नोपलिप्यते॥
yathā sarva-gataṁ saukṣmyād ākāśaṁ nopalipyate sarvatrāvasthito dehe tathātmā nopalipyate
Translation
As the all-pervading space, due to its subtlety, is not stained, so the self, seated everywhere in the body, is not stained.
Reflection
Notice the space in the room. Transfer that quality to the self behind your noticing.
Read this verse in its chapter: Chapter Thirteen
First analogy. Space is everywhere in the body, in the room, in the world. Smoke fills space, perfume fills space, sewage fills space. Space remains space. Nothing sticks to it because it is too subtle for anything to find purchase on. Akasha sarva-gatam saukshmyat nopalipyate. Now the application: the self, seated everywhere in the body, is similarly unstainable. Whatever happens in body or mind, the witness behind them does not absorb the residue. The analogy is gentle and effective. You can verify it yourself any time you notice space. Then transfer the verification to the self that sits behind your noticing. Stainless because subtle. The freedom in the verse is the freedom of space.