Srimad Bhagavatam Canto 11, Chapter 14, Text 19

SB 11.14.19

yathagnih su-samrddharcih
 karoty edhamsi bhasmasat
tatha mad-visaya bhaktir
 uddhavainamsi krtsnasah
 
Translation: 
 
My dear Uddhava, just as a blazing fire turns firewood into ashes, similarly, devotion unto Me completely burns to ashes sins committed by My devotees.
 
Purport: 
 
One should carefully note that the Lord refers to devotion that is like a blazing fire. To commit sinful activity on the strength of chanting the holy name is the greatest offense, and the devotion of one who commits this offense cannot be compared to a blazing fire of love for Krsna. As stated in the previous verse, a sincere loving devotee, because of immaturity or previous bad habits, may be disturbed by his senses even though he has accepted Lord Krsna as the only goal in his life. But if even by chance the devotee accidentally falls down without premeditation or indifference, the Lord immediately burns to ashes his sinful reactions, just as a blazing fire immediately consumes an insignificant piece of wood. Lord Krsna is glorious, and one who takes exclusive shelter of the Lord receives the unique benefits of devotional service to the Supreme Personality of Godhead.
Srimad Bhagavatam Canto 11, Chapter 14, Text 18
Srimad Bhagavatam Canto 11, Chapter 14, Text 20