1. Sign of having accepted a bona fide guru

    Only if we are very serious about understanding the science of God is a guru required. We should not try to keep a guru as a matter of fashion. One who has accepted a guru speaks intelligently. He never speaks nonsense. That is the sign of having accepted a bona fide guru.

    Srila Prabhupada; Science of Self-realization ch. 2a: What Is a Guru?