If a diseased person is being cured of the symptoms of his disease but does not care for the principles of healthy living, there is every possibility of a relapse. Similarly, the neophyte devotee serious about advancing in devotional service must carefully follow the principles of regulative devotional service; otherwise there is every possibility of his falling down. Strictly speaking, if a devotee ignores the regulative principles and acts according to his whims—if, for example, he does not eat kṛṣṇa-prasādam but eats anywhere and everywhere, such as in restaurants—there is every possibility of his falling down. If he accumulates money without spending it for devotional service, there is every possibility of his falling down. If he applies his energy not in the service of the Lord but in some material activity, there is every possibility of his falling down. If the devotee does not engage himself always in hearing and chanting the topics of Kṛṣṇa and His activities but instead indulges in idle talk, there is every chance of his falling down. If a neophyte devotee does not follow the orders of the spiritual master and simply officially sticks to the principles, or if he does not strictly follow the principles, there is every possibility of his falling down. To become greedy is another cause of falldown. And to associate with persons who are not in devotional service is the last word in māyā's allurements for causing a devotee to fall down.
In the Bhagavad-gītā (BG 18.5), Kṛṣṇa clearly states that sacrifice, charity, and penance are never to be given up by a transcendentalist. If he is at all intelligent he must continue these three activities, even if he is highly elevated. A devotee is naturally very humble, and even if he is highly elevated he does not consider himself to be so. A practical example is found in the life of the author of the Caitanya-caritāmṛta, Kṛṣṇadāsa Kavirāja Gosvāmī. He was a vastly learned scholar and a first-class devotee, yet he still referred to himself as the lowest of mankind, lower than the bacteria in the stool. He wrote that he was so sinful that no one should even utter his name, lest that person fall down! Of course, when a great devotee speaks this way, we should not believe that he is actually in the lower status of life; we should rather take it as evidence that out of humility a pure devotee never thinks he is elevated. He always thinks he is in the lowest status of spiritual life.
As stated above, in the Bhagavad-gītā Kṛṣṇa states that no one should give up the sacrificial portion of spiritual life. And the scriptures recommend that the best sacrifice in this Age of Kali is to chant Hare Kṛṣṇa, Hare Kṛṣṇa, Kṛṣṇa Kṛṣṇa, Hare Hare/ Hare Rāma, Hare Rāma, Rāma Rāma, Hare Hare. Therefore, a devotee's prime duty is to continue chanting this mahā-mantra, even if he is highly elevated. Otherwise, at any stage one can fall down.