Srimad Bhagavatam Canto 06, Chapter 03, Text 31

SB 6.3.31

tasmat sankirtanam visnor
 jagan-mangalam amhasam
mahatam api kauravya
 viddhy aikantika-niskrtam
 
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
Sukadeva Gosvami continued: My dear King, the chanting of the holy name of the Lord is able to uproot even the reactions of the greatest sins. Therefore the chanting of the sankirtana movement is the most auspicious activity in the entire universe. Please try to understand this so that others will take it seriously.
 
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 
 
We should note that although Ajamila chanted the name of Narayana imperfectly, he was delivered from all sinful reactions. The chanting of the holy name is so auspicious that it can free everyone from the reactions of sinful activities. One should not conclude that one may continue to sin with the intention of chanting Hare Krsna to neutralize the reactions. Rather, one should be very careful to be free from all sins and never think of counteracting sinful activities by chanting the Hare Krsna mantra, for this is another offense. If by chance a devotee accidentally performs some sinful activity, the Lord will excuse him, but one should not intentionally perform sinful acts.
Srimad Bhagavatam Canto 06, Chapter 03, Text 30
Srimad Bhagavatam Canto 06, Chapter 03, Text 32