Even a devotee may sometimes commit some sinful activity, either unknowingly or due to past sinful behavior. But if he sincerely repents, thinking, I should not have done this, but I am so sinful that I have again committed this sin, the Supreme Lord will excuse him on the basis of his genuine repentance. However, if he intentionally commits sinful activities, expecting that the Lord will forgive him because he is chanting Hare Krsna, that is inexcusable.

If one commits sinful activities on the strength of chanting the holy name, he commits nama-aparadha, or an offense against the holy name. Of the ten kinds of offenses, committing sins on the strength of chanting is the most serious. If after being freed from all sinful reactions by chanting Hare Krsna one again commits the same sins, he is guilty of a grievous crime. For an ordinary man, that sinful activity may not be regarded so seriously, but for one who is chanting Hare Krsna, it is a dangerous offense, just as it is a serious crime for a government officer in a high post to take advantage of his position and accept a bribe. Such men are the most punishable criminals. If a policeman steals, his crime and subsequent punishment are greater than that of an ordinary man who steals. That is the law. Similarly, one who takes gross advantage of the Hare Krsna mantra, thinking, I am chanting Hare Krsna, so even if I commit some sin Ill be excused, will not achieve the ultimate goal of chanting the holy name. He becomes entangled in a cycle: he is freed, then he again commits sin, then he is freed and again commits sin, freed and again commits sin. In this way he is never liberated.

Nevertheless, one should not think that ones sinful reactions will fail to be counteracted by the chanting of Hare Krsna. One of the ten offenses against the holy name of the Lord is to think that the holy name cannot eradicate sinful reactions. Those who cultivate offenseless chanting of the Hare Krsna maha-mantra should have firm faith in the words of the sastra that declare the chanting of the holy names of Krsna to be supremely powerful. As the Visnudutas say here, The chanting of the holy name of Lord Visnu is the best process of atonement for all kinds of sinners. But very often the difficulty is that one will chant Hare Krsna and again commit sin.