"The first principle is that one should be prepared to sacrifice any, everything for Kṛṣṇa. Everything. It doesn't matter—my fate, my honor, my money, my prestige. He doesn't care. Kṛṣṇa must be satisfied. Just (like) Arjuna did. Arjuna didn't like to fight, to kill on the other side his brother, his grandfather. No. But when he understood, 'No, Kṛṣṇa wants it. Yes, kariṣye vacanaṁ tava (BG 18.73). That's all right.' This is Kṛṣṇa consciousness. No consideration for anything else. Simply to satisfy Kṛṣṇa. Satisfy Kṛṣṇa or Kṛṣṇa's representative. The same thing. That is bhakti."
(Srila Prabhupada Lecture, Bombay, December 26, 1972)