(Srila Prabhupada, New Remuna Dhama, Toronto, 1976)
"The purpose of life is to understand Krishna. There is no other business in this human form of life, but because we have given up Krishna we have invented so many occupational duties. So these so-called occupational duties, running here and there on motorcar, is not the end of life. There is something more for the human being, and that is divya-jnana. Tapo divyam putraka yena suddhyed sattvam, yasmad brahma-saukhyam tv anantam [SB 5.5.1]. Why shall I purify my existence? Because you want happiness. That is your desire. So you'll get brahma-saukhyam, the greatest happiness, which will never end. If you purify your existence by tapasya then you will be happy eternally. There will be no end. Here in this material world any happiness is temporary -- either for five minutes or five days or five years or five hundred years or five millions of years. It will end. But if you purify your existence, then the happiness will never end. Tapo divyam putraka yena suddhyed sattvam, yasmad brahma-saukhyam tv anantam [SB 5.5.1]. Anantam means unlimited. It is very serious thing, and it is offered to the human being. So anyone can take advantage of this opportunity and make his life successful."
(Srila Prabhupada lecture, Toronto, June 17, 1976)