If one sincerely searches for spiritual salvation, then Krishna, being situated in everyone’s heart, gives him the intelligence to find a suitable spiritual master. By the grace of a spiritual master, one gets the proper instructions and advances in his spiritual life.
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.
If 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 bona fide spiritual master, under the guidance of authorities, can turn anyone to the Vaisnava cult so that naturally he may come to the topmost position of a brahmana.
One must execute devotional service under the guidance of a devotee or directly under the guidance of the Supreme Personality of Godhead. It is not possible, however, to train oneself without guidance from the spiritual master.
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.