Śrī Āvirhotra replied: Prescribed duties, nonperformance of such duties, and forbidden activities are topics one can properly understand through authorized study of the Vedic literature. This difficult subject matter can never be understood by mundane speculation. The authorized Vedic literature is the sound incarnation of the Personality of Godhead Himself, and thus Vedic knowledge is perfect. Even the greatest learned scholars are bewildered in their attempts to understand the science of action if they neglect the authority of Vedic knowledge.
Srimad Bhagavata Purana
श्रीमद्भागवतमहापुराणम्
मूल श्लोकः
आविर्होत्र उवाच । कर्माकर्मविकर्मेति वेदवादो न लौकिकः । वेदस्य चेश्वरात्मत्वात्तत्र मुह्यन्ति सूरयः
āvirhotra uvāca | karmākarmavikarmeti vedavādo na laukikaḥ | vedasya ceśvarātmatvāttatra muhyanti sūrayaḥ
SB 11.3.43