In his illuminating discourse to Arjuna on desires, Sri Krishna prescribes sense control as the first discipline to free oneself from them: ‘Therefore, control your senses at the outset and kill this destroyer of Knowledge and realization.’ Our five sense organs are like windows to the external world and bring us perceptual knowledge and, along with it, the memory and desire from these perceptions. He who does not want to be swayed by desires needs to be careful about the sensory inputs to his mind. Only that can help in purification of the mind and help him gain mastery over it. Says the Chandogya Upanishad, ‘If the food is pure the mind too becomes pure.’ In his commentary, Sri Shankara clarifies that ‘food’ does not mean just physical food, but the input through all the sense organs.’
Senses mean not only the five sense organs, but also the mind. Mind is the inner organ that is looked upon as the king of the senses. Since in any perception the mind connects itself to the concerned sense organ, mind control is fundamental to control of desires.
Who controls the mind? It is buddhi, the discriminative faculty. However, it lies dormant in a person swayed by desire. Our degradation is triggered when our will (the dynamic aspect of buddhi) gets hooked to the desire. When someone succumbs to a desire, his will does not have a separate existence: it merges with the succumbing mind and the senses.
A slave to sense enjoyments (or any bad habit for that matter) identifies himself only with his mind and the body, and is not conscious of a separate will. He begins to turn a new leaf only when he succeeds in freeing his will from the hold of desires. Thus, though the will is bound, it is through the will that release is possible.
Though Sri Krishna includes buddhi also among the seat of desire, (3.40) he says elsewhere in the Gita, ‘Seek refuge in buddhi.’ (2.49) Thus, all efforts at mind control basically mean awakening buddhi, which amounts to strengthening the will.