When the senses contact sense objects, a person experiences cold or heat, pleasure or pain. These experiences are fleeting; they come and go. Bear them patiently, Arjuna. Those who are not affected by these changes, who are the same in pleasure and pain, are truly wise and fit for immortality. Assert your strength and realize this!... The disunited mind is far from wise; how can it meditate? How can it be at peace? When you know no peace, how can you know joy? When you let your mind follow the call of the senses, they carry away your better judgement as storms drive a boat off its charted course on the sea. Use all of your power to free the senses from attachment and aversion alike, and live in the full wisdom of the Self.

(The Bhagavat Gita)