Today many scholars defend the science of religion, and they have some conception of the Supreme Personality of Godhead, but religion without practical experience of the Supreme Personality of Godhead is no religion at all. Srimad-Bhagavatam describes this as a form of cheating. Religion means abiding by the orders of Krsna, the Supreme Personality of Godhead. If one is not qualified to talk with Him and take lessons from Him, how can one understand the principles of religion? Thus talks of religion or religious experience without Krsna consciousness are a useless waste of time.
From Srila Prabhupada’s purport to CC Madhya 4.95