Ashtavakra Gita 17.2 -

One becomes a Knower on knowing the supreme Truth. What is the supreme Truth? It is the imperishable Self he refers to repeatedly as the ‘I’. Yes, the Self is the ‘I’, and ‘I’ is the Self. Its magnitude is infinite. It witnesses the endless Universe with all its variety. To be able to do so, it has to be infinite indeed. It is at zero distance from oneself, one’s body, mind, intelligence and ego.

The moment the measure of the Self is felt, the whole Universe becomes that, his Self. He sees the Universe within himself, like thoughts and emotions. At no time does anyone see any gross object outside. What is seen and felt is the inner imprint of and by the mind. Where is then the Universe besides oneself, one’s Self?

Whatever takes place in the Universe seemingly, grossly, on truthful introspection, transpires within the Knower, his Self. There is no separation between the seeing Self and seen Universe. The Self alone fills the whole Universe. So the interaction is within the Knower, as in dream state, like the roaring waves in the sea.

Take a huge drum of water from a lake. Lift it to a great height and pour it into the lake. It may cause a huge splash. But will anything happen to the poured water or the lake?

Let anything transpire in the world, in the Self-universe. No scar or dent will be caused to the Self. It is lack of Self-knowledge that makes one suffer. To the Self-knower there is no grief or its opposite! It is all a uniformness, sameness and singularness!