By knowing which you will no more court any further delusion, and whereby you will see all beings in the Self and hence in Me, the Supreme.
Essence of spirituality consists in getting exposed to the singular Self and realizing its fullness. As a result, the delusion of the mind will be attenuated. Delusion makes one think that the body is the Self. Body is something the Self animates and activates.
Self-knowledge has the power to eliminate delusion of the mind and intelligence. It will also imbue expansion and clarity, leading the seeker to realize that all beings are verily abiding in the Self. Grossness and externality are ideas created by the mind, which is just a functional note of the Self.
Self is the ground for all experiences. Objectivity, grossness, externality, variety and allied features are the creation of Consciousness. Their locus is inner.
Krishna adds that the vision goes a step further. The whole abidance of everything is in the supreme Reality, God. Spiritual vision will not be complete until the seeker reaches this acme.