In plain words
The Self is untouched by mind and senses, yet is the mind of the mind and the eye of the eye. Those instruments cannot grasp it. I am that imperishable Self, always established in itself.
Word for word
He remains unassociated with mind, eye and the rest; He is the mind of the mind, the eye of the eye and the source of the other faculties; by mind, eye and the rest He cannot be grasped. I am that imperishable, ever-established Self.