"Duties (dharma) executed by men, regardless of occupation, are only so much useless labor if they do not provoke attraction for the message of the Supreme Lord." (S.B.1:2:8) These karma-kāṇḍa activities are required as long as one has not developed Kṛṣṇa consciousness. If one is developed in Kṛṣṇa consciousness, there is no need to execute the prior regulative principles of karma-kāṇḍa. Śrīla Mādhavendra Purī said, "O regulative principles of karma-kāṇḍa, please excuse me. I cannot follow all these regulative principles, for I am fully engaged in devotional service." He expressed the desire to sit somewhere beneath a tree and continue chanting the Hare Kṛṣṇa mahā-mantra. Consequently he did not execute all the regulative principles. Similarly, Haridāsa Ṭhākura was born in a Mohammedan family. From the very beginning of his life he was never trained in the karma-kāṇḍa system, but because he was always chanting the holy name of the Lord, Śrī Caitanya Mahāprabhu accepted him as nāmācārya, the authority in chanting the holy name. As Jaḍa Bharata, Bharata Mahārāja was always engaged in devotional service within his mind. Since he had executed the regulative principles continuously for three lives, he was not interested in continuing to execute them, although his brāhmaṇa father wanted him to do so.
(Srimad Bhagavatam------5:9:4------purport).

Even if a devotee comes from a family of dog-eaters, if he surrenders to the Personality of Godhead he immediately becomes a qualified brāhmaṇa and is immediately fit to perform yajña, whereas a person born in a family of brāhmaṇas has to wait until completing the reformatory processes before he may be called saṁskṛta, purified. It is further said in Śrīmad-Bhāgavatam (12.1.40):
asaṁskṛtāḥ kriyā-hīnā rajasā tamasāvṛtāḥ
prajās te bhakṣayiṣyanti mlecchā rājanya-rūpiṇaḥ
"In the Age of Kali, mlecchas, or lowborn people who have not undergone the purifying process of saṁskāra, who do not know how to apply that process in actual life, and who are covered by the modes of passion and ignorance will take the posts of administrators. They will devour the citizens with their atheistic activities." A person who is not purified by the prescribed process of saṁskāra is called asaṁskṛta, but if one remains kriyā-hīna even after being purified by initiation—in other words, if one fails to actually apply the principles of purity in his life—he remains an unpurified mleccha or yavana. On the other hand, we find that Haridāsa Ṭhākura, although born in a mleccha or yavana family, became Nāmācārya Haridāsa Ṭhākura because he performed the nāma-yajña a minimum of 300,000 times every day.

(Sri Caitanya Caritamrta------3:3:124-------purport).

Advanced yogīs are not very much attracted to the rituals of the scriptures, but they automatically become attracted to the yoga principles, which can elevate them to complete Kṛṣṇa consciousness, the highest yoga perfection. In the Śrīmad-Bhāgavatam (3.33.7), such disregard of Vedic rituals by the advanced transcendentalists is explained as follows:

aho bata śva-paco 'to garīyān
yaj-jihvāgre vartate nāma tubhyam
tepus tapas te juhuvuḥ sasnur āryā
brahmānūcur nāma gṛṇanti ye te
"O my Lord! Persons who chant the holy names of Your Lordship are far, far advanced in spiritual life, even if born in families of dog-eaters. Such chanters have undoubtedly performed all kinds of austerities and sacrifices, bathed in all sacred places, and finished all scriptural studies."

The famous example of this was presented by Lord Caitanya, who accepted Ṭhākura Haridāsa as one of His most important disciples. Although Ṭhākura Haridāsa happened to take his birth in a Muslim family, he was elevated to the post of nāmācārya by Lord Caitanya due to his rigidly attended principle of chanting three hundred thousand holy names of the Lord daily: Hare Kṛṣṇa, Hare Kṛṣṇa, Kṛṣṇa Kṛṣṇa, Hare Hare/ Hare Rāma, Hare Rāma, Rāma Rāma, Hare Hare. And because he chanted the holy name of the Lord constantly, it is understood that in his previous life he must have passed through all the ritualistic methods of the Vedas, known as śabda-brahma. Unless, therefore, one is purified, one cannot take to the principles of Kṛṣṇa consciousness or become engaged in chanting the holy name of the Lord, Hare Kṛṣṇa.

(Bhagavad-Gita------6:44------purport).

Since he was born in a Muslim family, Śrīla Haridāsa Ṭhākura could not enter the temple of Jagannātha due to temple restrictions. Nonetheless, he was recognized by Śrī Caitanya Mahāprabhu as Nāmācārya Haridāsa Ṭhākura. Haridāsa Ṭhākura, however, considered himself unfit to enter the Jagannātha temple. Śrī Caitanya Mahāprabhu could have personally taken Haridāsa Ṭhākura into the Jagannātha temple if He wished, but the Lord did not like to disturb a popular custom. Consequently the Lord asked His servant simply to look at the Viṣṇu wheel on top of the temple and offer obeisances (namaskāra). This means that if one is not allowed to enter the temple, or if he thinks himself unfit to enter the temple, he can look at the wheel from outside the temple, and that is as good as seeing the Deity within.

(Sri Caitanya Caritamrta------2:11:195-------purport).

This verse definitely proves that Śrīla Śukadeva Gosvāmī did not refuse to teach Sūta Gosvāmī about the transcendental science nor did the sages of Naimiṣāraṇya refuse to hear lessons from him because of his inferior birth. This means that thousands of years ago there was no bar to learning or preaching the transcendental science because of inferior birth. The rigidity of the so-called caste system in Hindu society became prominent within only one hundred years or so when the number of dvija-bandhus, or disqualified men in the families of higher castes, increased. Lord Śrī Caitanya revived the original Vedic system, and He elevated Ṭhākura Haridāsa to the position of nāmācārya, or the authority in preaching the glories of the holy name of the Lord, although His Holiness Śrīla Haridāsa Ṭhākura was pleased to appear in a family of Mohammedans.

(Srimad Bhagavatam------1:18:18------purport).