It is said in the Srimad-Bhagavatam that this devotional service is so powerful that even if a devotee occasionally falls down from the standard there is no loss for him. If he is sincere, he will automatically rectify his error and Lord Krsna immediately purifies him from within. This is stated in the Bhagavad-gita also, that for the devotee Krsna gives all protection, and there is never any loss for him. But if one is not engaged in Krsna Consciousness, there is no gain for him in any position of material life. So we must stick firmly to the chanting of the Holy Name and following the rules. This will keep us from being tricked by Maya. But there is no question of disappointment for some temporary bewilderment.
Letter to Sucandra, 19 February, 1970