We can wash the skin of our bodies with a bath, but through asana practice we not only purify our blood and cells, we are cleansing the inner body as we practice.
The battle of yoga is with the body and with the ego. You must conquer your ego, or small self, so that you can let your soul, your big Self, be victorious.
As a mighty river which when properly harnessed by dams and canals, creates a vast reservoir of water, prevents famine and provides abundant power for industry; so also the mind, when controlled, provides a reservoir of peace and generates abundant energy for the human uplift.
While doing the postures, your mind should be in half-consciousn ess, which does not mean sleep. It means silence, emptiness, space, which can then be filled with an acute awareness of the sensations given by the posture. You watch yourself from inside. It is a full silence.
