Srimad Bhagavatam Canto 11, Chapter 14, Text 21

SB 11.14.21

bhaktyaham ekaya grahyah
 sraddhayatma priyah satam
bhaktih punati man-nistha
 sva-pakan api sambhavat
 
Translation: 
 
Only by practicing unalloyed devotional service with full faith in Me can one obtain Me, the Supreme Personality of Godhead. I am naturally dear to My devotees, who take Me as the only goal of their loving service. By engaging in such pure devotional service, even the dog-eaters can purify themselves from the contamination of their low birth.
 
Purport: 
 
Sambhavat indicates jati-dosat, or the pollution of low birth. Jati-dosa does not refer to mundane social, economic or professional status, but rather to one’s degree of spiritual enlightenment. All around the world, many people are born into rich and powerful families, but they often acquire abominable habits that are part of their so-called family tradition. However, even unfortunate persons who are taught from birth to engage in sinful activities can at once be purified by the potency of pure devotional service. Such service must have Lord Krsna as the only goal (man-nistha), must be rendered with full faith (sraddhaya), and must be unalloyed, or without any selfish motivation (ekaya).
Srimad Bhagavatam Canto 11, Chapter 14, Text 20
Srimad Bhagavatam Canto 11, Chapter 14, Text 22