The first principle is one must be very enthusiastic. He must believe that Krsna has said that, na me bhaktah pranasyati, "My devotee will never be vanquished." So "Let me becomes Krsna's devotee sincerely. I must become Krsna's devotee sincerely." This is called enthusiasm. Then dhairyat. "I have become Krsna's devotee, but still I'm not feeling happy. How is that?" So therefore you have to become patient. The enthusiasm must be there, you must be patient also. And niscayat. Niscayat means you must be confident. "Oh, Krsna has said that His devotee will never be vanquished, so surely I shall not be vanquished, even though I don't feel now. Let me do my duty."

>>> Ref. VedaBase => Bhagavad-gita 2.13-17 — Los Angeles, November 29, 1968