In spiritual life, one must conduct one's whole life under the guidance of the guru. Only one who executes his spiritual life under the direction of the spiritual master can achieve the mercy of Krishna.
A. C. Bhaktivedanta Swami PrabhupadaYou should not be carried away by the dictation of the mind, but the mind should be carried by your dictation.
A. C. Bhaktivedanta Swami PrabhupadaIf after accepting the spiritual master and being initiated one does not follow the rules and regulations of devotional service, then he is again fallen.
A. C. Bhaktivedanta Swami PrabhupadaFirst birth is from your parents, but real birth, real life, begins when one accepts a bona fide spiritual master and renders service unto him. Then the path is open for going back to home, back to Godhead, to live eternally in full knowledge and full bliss and in association with the Supreme Personality of Godhead Himself, Lord Krishna.
A. C. Bhaktivedanta Swami Prabhupada