The real problem of life in the material world is to solve the question of birth, death, old age and disease.
Srimad Bhagavatam 2.3.2-7,
Krishna, Krishna’s service and love of Krishna are the three great riches of life.
Madhya Lila 20.143
Life without love is useless and poor they say, Appoint me in thy service, Oh Lord with Love as my pay.
That is my ideal of life, to form a nice group of devotees to perform Sankirtana and to distribute our books in wider circles.
Letter to Gurudasa – Los Angeles 5 February, 1969.
One has to continue chanting the Hare Krishna mantra and preaching the chanting of this mantra because such preaching and chanting constitute the perfection of life.
Purport on Srimad Bhagavatam 4.24.67