Bhagavad Gita Chapter 18 Verse 22
यत्, तु, कृत्स्न्नवत्, एकस्मिन्, कार्ये, सक्तम्, अहैतुकम्,
अतत्त्वार्थवत्, अल्पम्, च, तत्, तामसम्, उदाहृतम्।।22।।
Yat’, tu, krtsannvat’, ekasmin’, kaarye, sakttam’, ahaetukam’,
Atattvaarthvat’, alpam’, ch, tat’, taamsam’, udaahrtam’ ||22||
Translation: (Tu) But (yat’) the knowledge which (ekasmin’) one (kaarye) in implementing body only (krtsannvat’) as if it were all / whole (sakttam’) is engrossed/attached (ch) and which (ahaetukam’) is irrational (atattvaarthvat’) without any understanding and reason (alpam’) is trivial (tat’) that (taamsam’) Tamas (udaahrtam’) is said to be. (22)
Translation: But that knowledge which is only engrossed in one implementing body as if it were all and which is irrational without any understanding and reason and is trivial – that is said to be Tamas.