Bhagavad Gita 18.22

यत्तु कृत्स्नवदेकस्मिन्कार्ये सक्तमहैतुकम्।अतत्त्वार्थवदल्पं च तत्तामसमुदाहृतम्॥

yattu kṛtsnavadekasminkārye saktamahaitukam |atattvārthavadalpaṃ ca tattāmasamudāhṛtam ||

But that which clings to one single effect as if it were the whole, without reason, without any foundation in Truth, and is trivial—that is declared to be Tamasic.

But that which clings blindly to one idea as if it were all, without logic, truth, or insight, has its origin in darkness.

Our plain-language meaning of this verse is waiting for scholar review.