By the grace of the spiritual master the cloud of the mercy of the Personality of Godhead is brought in, and then only, when the rains of Krishna consciousness fall, can the fire of material existence be extinguished.
A. C. Bhaktivedanta Swami PrabhupadaSince one cannot visually experience the presence of the Supersoul, He appears before us as a liberated devotee. Such a spiritual master is none other than Krishna himself.
A. C. Bhaktivedanta Swami PrabhupadaThe spiritual master and Krishna are two parallel lines. The train, on two tracks, moves forward. The spiritual Master and Krishna are like these two tracks. They must be served simultaneously. Krishna helps one to find bona fide Spiritual Master and bona fide Spiritual Master helps one to understand Krishna. If one does not get bona fide Spiritual Master, then how he can ever understand Krishna ? You cannot serve Krishna without Spiritual Master, or serve just Spiritual Master without serving Krishna. They must be served simultaneously.
A. C. Bhaktivedanta Swami PrabhupadaTherefore a person fully absorbed in the bodily concept of life is surely killing himself by not making spiritual progress. Such a person is called pasu-ghna. Especially excluded from spiritual life are the animal hunters, who are not interested in hearing and chanting the holy name of the Lord. Such hunters are always unhappy, both in this life and in the next. It is therefore said that a hunter should neither die nor live because for such persons both living and dying are troublesome.
A. C. Bhaktivedanta Swami PrabhupadaOut of many millions of wandering living entities, one who is very fortunate gets an opportunity to associate with a bonafide spiritual master by the grace of Krishna. By the mercy of both Krishna and the spiritual masters, such a person receives the seed of the creeper of devotional service.
A. C. Bhaktivedanta Swami Prabhupada