Bhagavad-gītā 18.22
BG 18.22
Open the full passageयत्तु कृत्स्नवदेकस्मिन्कार्ये सक्तमहैतुकम् । अतत्त्वार्थवदल्पं च तत्तामसमुदाहृतम् ॥२२॥
Sanskrit
yat tu kṛtsna-vad ekasmin kārye saktam ahaitukam atattvārtha-vad alpaṁ ca tat tāmasam udāhṛtam
Translation
And that knowledge by which one is attached to one kind of work as the all in all, without knowledge of the truth, and which is very meager, is said to be in the mode of darkness.