te ca hy arvāktanayā nija-loka-yātrayāndha-paramparayāśvastās tamasy andhe svayam eva prapatiṣyanti
te - those people not following the Vedic principles; ca - and; hi - certainly; arvāktanayā - deviating from the eternal principles of Vedic religion; nija-loka-yātrayā - by a practice arrived at by their own mental concoction; andha-paramparayā - by a disciplic succession of blind. ignorant people; āśvastāḥ - being encouraged; tamasi - into the darkness of ignorance; andhe - blindness; svayam eva - themselves; prapatiṣyanti - will fall down.
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).