This sutra is in the nature of a summation and emphasizes the fact that the mind, being stilled and quiescent through the practise of concentration [417] and meditation, becomes the reflector of "that which is above and of that which lies below." It is the transmitter of the knowledge of the self to the physical brain of the man in incarnation, and the transmitter also of all that which the self knows and perceives. The field of knowledge is seen and known. The knower is also perceived, and the "perception of all objects" becomes possible. It becomes literally true, therefore, that for the yogin nothing remains hidden or unknown. Information on all subjects becomes possible to him, for he has an instrument which he can use to ascertain that which the soul knows concerning the Kingdom of God, the realm of spiritual truth. He can also enter into communication and convey to the soul that which is known to the man in physical incarnation. Thus the knower, the field of knowledge and knowledge itself are brought into conjunction and the medium of this union is the mind.