CC Madhya 25.136

bhaktyāham ekayā grāhyaḥ
śraddhayātmā priyaḥ satām
bhaktiḥ punāti man-niṣṭhā
śva-pākān api sambhavāt
Word for word: 
bhaktyā — by devotional service; aham — I, the Supreme Personality of Godhead; ekayā — unflinching; grāhyaḥ — obtainable; śraddhayā — by faith; ātmā — the most dear; priyaḥ — to be served; satām — by the devotees; bhaktiḥ — the devotional service; punāti — purifies; mat-niṣṭhā — fixed only on Me; śva-pākān — the lowest grade of human beings, who are accustomed to eating dogs; api — certainly; sambhavāt — from all faults due to birth and so on.
Translation: 
“[Lord Kṛṣṇa said:] ‘Being very dear to the devotees and sādhus, I am attained through unflinching faith and devotional service. This bhakti-yoga system, which gradually increases attachment for Me, purifies even a human being born among dog-eaters. That is to say, everyone can be elevated to the spiritual platform by the process of bhakti-yoga.’
Purport: 

This verse is from Śrīmad-Bhāgavatam (11.14.21).