SB 11.20.26

sve sve ’dhikāre yā niṣṭhā
 sa guṇaḥ parikīrtitaḥ
karmaṇāṁ jāty-aśuddhānām
 anena niyamaḥ kṛtaḥ
guṇa-doṣa-vidhānena
 saṅgānāṁ tyājanecchayā
Word for word: 
sve sve — each in his own; adhikāre — position; — which; niṣṭhā — steady practice; saḥ — this; guṇaḥ — piety; parikīrtitaḥ — is thoroughly declared; karmaṇām — of fruitive activities; jāti — by nature; aśuddhānām — impure; anena — by this; niyamaḥ — disciplinary control; kṛtaḥ — is established; guṇa — of piety; doṣa — of sin; vidhānena — by the rule; saṅgānām — of association with different types of sense gratification; tyājana — of renunciation; icchayā — by the desire.
Translation: 
It is firmly declared that the steady adherence of transcendentalists to their respective spiritual positions constitutes real piety and that sin occurs when a transcendentalist neglects his prescribed duty. One who adopts this standard of piety and sin, sincerely desiring to give up all past association with sense gratification, is able to subdue materialistic activities, which are by nature impure.
Purport: 

Lord Kṛṣṇa here explains more clearly that those persons directly engaged in self-realization either through jñāna-yoga or bhakti-yoga need not give up their regular duties and perform special penances to atone for an accidental falldown. The actual purpose of Vedic literature is to direct one back home, back to Godhead, and not to encourage material sense gratification. Although the Vedas recommend innumerable rituals for promotion to heavenly planets and enjoyment of all varieties of material opulence, such materialistic rewards are meant only to engage materialistic people, who otherwise would become demoniac. To purify an accidental falldown, one who is engaged in transcendental realization need not adopt any procedure beyond his own spiritual practice. The words saṅgānāṁ tyājanecchayā indicate that one should not practice Kṛṣṇa consciousness or self-realization superficially or casually; rather, one should sincerely and earnestly desire freedom from one’s past sinful life. Similarly, the words yā niṣṭhā indicate that one must constantly practice Kṛṣṇa consciousness. Thus, essential piety is to give up material sense gratification and engage in the loving service of the Lord. One who engages his senses, mind and intelligence twenty-four hours a day in the Lord’s service is the most pious person, and the Lord personally protects such a surrendered soul.