Like space itself

yathā sarvagataṃ saukṣmyādākāśaṃ nopalipyatesarvatrāvasthito dehe tathātmā nopalipyate

As all-pervading space, being so subtle, is never stained, so the Self, present throughout the body, is never stained.

What it means

Krishna gives an image. Akasha, space, is everywhere. Smoke drifts through it, dust floats in it, yet space is never dirtied. It's too subtle. The Self is like that, pervading the body completely, yet never stained by anything that happens there.

The story

Arjuna lives among dust, smoke and blood on this battlefield. Krishna points to the space all of it moves through, untouched. The Self is that space.

In your life

After a smoky campfire, look up. The sky is clear. Next time you feel weighed down by something that happened, imagine your inner self as that clear sky.