CC Madhya 22.143

ajñāne vā haya yadi ‘pāpa’ upasthita
kṛṣṇa tāṅre śuddha kare, nā karāya prāyaścitta
Word for word: 
ajñāne — by ignorance; vā — or; haya — there are; yadi — if; pāpa — sinful activities; upasthita — present; kṛṣṇa — Lord Kṛṣṇa; tāṅre — him (the devotee); śuddha kare — purifies; nā karāya — does not cause; prāyaścitta — atonement.
Translation: 
“If, however, a devotee accidentally becomes involved in a sinful activity, Kṛṣṇa purifies him. He does not have to undergo the regulative form of atonement.
Purport: 

Kṛṣṇa purifies from within as the caittya-guru, the spiritual master within the heart. This is described in the following verse from Śrīmad-Bhāgavatam (11.5.42).