Chapter 2, Solaka 58.
As a tortoise draws his limbs (into the shell) likewise, a yogi draws his senses from worldly objects or the objects of the senses from every side. This is the art of meditation, when we draw the mind inside by using any method such as observation,nam Japa,observing our breath Vipassana. now what we are doing ? we are trying to withdraw our senses from outside (worldly objects) that is called (Antarmukha); then by practicing these methods we can find that eternal bliss or eternal peace in our hearts. which language never can describe. it is our destination.