Srimad-Bhagavatam: Canto 5 - Chapter 1 - Verse 11

Sanskrit:

ते च ह्यर्वाक्तनया निजलोकयात्रयान्धपरम्परयाऽऽश्वस्तास्तमस्यन्धे स्वयमेव प्रपतिष्यन्ति ॥ ११ ॥

ITRANS:

te ca hy arvāktanayā nija-loka-yātrayāndha-paramparayāśvastās tamasy andhe svayam eva prapatiṣyanti.

Translation:

Low-class people, due to their gross ignorance, introduce a system of religion that deviates from the Vedic principles. Following their own mental concoctions, they automatically fall down into the darkest regions of existence.

Purport:

In this connection, one may see Bhagavad-gītā, Chapter Sixteen, where there is a description of the downfall of the asuras (16.16 and 16.23).