The 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 spiritula 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. — Letter to Mahapurusha, 12th Feb, 1968.
The genuine Guru is God's representative and he speaks about God and nothing else.
Holy name alone is sufficient to take you back home back to godhead. However to cultivate the mood of surrender You need a Guru.
If we take shelter of the lotus feet of the spiritual master, we can become free from illusion, fear and distress. If we wholeheartedly beg for his mercy without any deceit then the spiritual master bestows all auspiciousness upon us.