He who knows that indestructible being, obtains (what is) the highest and indestructible, he without a shadow, without a body, without colour, bright,— yes, O friend, he who knows it, becomes all-knowing, becomes all. On this there is this Sloka:

In plain words: Whoever knows this Self that cannot be destroyed reaches the highest thing. This Self has no shadow, no body and no color, and it shines. Knowing it, a person comes to know everything and becomes one with everything.