As far as possible, a devotee is very cautious so that he does not do anything that could disrupt his wholesome condition. He knows that perfection in his activities depends on his progressive realization of Kṛṣṇa consciousness. Sometimes, however, it may be seen that a person in Kṛṣṇa consciousness commits some act which may be taken as most abominable socially or politically. But such a temporary falldown does not disqualify him. In the Śrīmad-Bhāgavatam it is stated that if a person falls down but is wholeheartedly engaged in the transcendental service of the Supreme Lord, the Lord, being situated within his heart, purifies him and excuses him from that abomination. The material contamination is so strong that even a yogī fully engaged in the service of the Lord sometimes becomes ensnared; but Kṛṣṇa consciousness is so strong that such an occasional falldown is at once rectified. Therefore the process of devotional service is always a success. No one should deride a devotee for some accidental falldown from the ideal path, for, as explained in the next verse, such occasional falldowns will be stopped in due course, as soon as a devotee is completely situated in Kṛṣṇa consciousness.
Therefore a person who is situated in Kṛṣṇa consciousness and is engaged with determination in the process of chanting Hare Kṛṣṇa, Hare Kṛṣṇa, Kṛṣṇa Kṛṣṇa, Hare Hare/ Hare Rāma, Hare Rāma, Rāma Rāma, Hare Hare should be considered to be in the transcendental position, even if by chance or accident he is found to have fallen. The words sādhur eva, "he is saintly," are very emphatic. They are a warning to the nondevotees that because of an accidental falldown a devotee should not be derided; he should still be considered saintly even if he has accidentally fallen down. And the word mantavyaḥ is still more emphatic. If one does not follow this rule, and derides a devotee for his accidental falldown, then one is disobeying the order of the Supreme Lord. The only qualification of a devotee is to be unflinchingly and exclusively engaged in devotional service. ... No one should take advantage of this verse and commit nonsense and think that he is still a devotee. If he does not improve in his character by devotional service, then it is to be understood that he is not a high devotee.