256
Śrīmad-Bhāgavatam
[Canto 6, Ch. 13]
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.
TEXT 10
श्रीशुक उवाच
एवं सञ्चोदितो विप्रैर्मरुत्वानहनद्रिपुम् ।
ब्रह्महत्या हते तस्मिन्नाससाद वृषाकपिम् ॥१०॥