It is said in the Bṛhad-viṣṇu Purāṇa:

nāmno hi yāvatī śaktiḥ
 pāpa-nirharaṇe hareḥ
tāvat kartuṁ na śaknoti
 pātakaṁ pātakī naraḥ

Also, in the Prema-vivarta by Jagadānanda Paṇḍita it is said:

eka kṛṣṇa-nāme pāpīra yata pāpa-kṣaya
 bahu janme sei pāpī karite nāraya

This means that by once chanting the holy name of the Lord, one can be freed from the reactions of more sins that he can even imagine performing. The holy name is so spiritually potent that simply by chanting the holy name one can be freed from the reactions to all sinful activities. What, then, is to be said of those who chant the holy name regularly or worship the Deity regularly? For such purified devotees, freedom from sinful reaction is certainly assured. This does not mean, however, that one should intentionally commit sinful acts and think himself free from the reactions because he is chanting the holy name. Such a mentality is a most abominable offense at the lotus feet of the holy name. Nāmno balād yasya hi pāpa-buddhiḥ: the Lord’s holy name certainly has the potency to neutralize all sinful activities, but if one repeatedly and intentionally commits sins while chanting the holy name, he is most condemned.

These verses name the performers of various sinful deeds. In the Manu-saṁhitā the following names are given. A son begotten by a brāhmaṇa and born from the womb of a śūdra mother is called a pāraśava or niṣāda, a hunter accustomed to stealing. A son begotten by a niṣāda in the womb of a śūdra woman is called a pukkasa. A child begotten by a kṣatriya in the womb of the daughter of a śūdra is called an ugra. A child begotten by a śūdra in the womb of the daughter of a kṣatriya is called a kṣattā. A child begotten by a kṣatriya in the womb of a lower-class woman is called a śvāda, or dog-eater. All such offspring are considered extremely sinful, but the holy name of the Supreme Personality of Godhead is so strong that all of them can be purified simply by chanting the Hare Kṛṣṇa mantra.

The Hare Kṛṣṇa movement offers everyone a chance to be purified, regardless of birth or family. As confirmed in Śrīmad-Bhāgavatam (2.4.18):

kirāta-hūṇāndhra-pulinda-pulkaśā
 ābhīra-śumbhā yavanāḥ khasādayaḥ
ye ’nye ca pāpā yad-apāśrayāśrayāḥ
 śudhyanti tasmai prabhaviṣṇave namaḥ

“Kirātas, Hūṇas, Āndhras, Pulindas, Pulkaśas, Ābhīras, Śumbhas, Yavanas, members of the Khasa races, and even others addicted to sinful acts can be purified by taking shelter of devotees of the Lord, for He is the supreme power. I beg to offer my respectful obeisances unto Him.” Even such sinful persons can certainly all be purified if they chant the holy name of the Lord under the direction of a pure devotee.

Herein the sages encourage King Indra to kill Vṛtrāsura even at the risk of brahma-hatyā, the killing of a brāhmaṇa, and they guarantee to release him from sinful reactions by performing an aśvamedha-yajña. Such purposefully devised atonement, however, cannot relieve the performer of sinful acts. This will be seen from the following verse.