Since 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 Lord has different names according to His different activities. For example, His name is Madhusรผdana because He killed the demon of the name Madhu; His name is Govinda because He gives pleasure to the cows and to the senses
A. C. Bhaktivedanta Swami PrabhupadaA spiritual master who is one hundred percent Krishna conscious is the bona fide spiritual master.
A. C. Bhaktivedanta Swami Prabhupada