As long as you do not feel the serenity in the body, in each and every joint, there is no chance for emancipation. You are in bondage. So while you are sweating and aching, let your heart be light and let it fill your body with gladness. You are not only becoming free, but you are also being free. What is not to be glad about? The pain is temporary. The freedom is permanent.
B.K.S. IyengarDeath is unimportant to a yogi; he does not mind when he is going to die. What happens after death is immaterial to him. He is only concerned with life-with how he can use his life for the betterment of humanity. Having undergone various types of pain in his life and having acquired a certain mastery over pain, he develops compassion to help society and maintains himself in purity and holiness. The yogi has no interest beyond that.
B.K.S. Iyengar