Bhagavad Gita Chapter 18 Verse 35

Gita 18.35

यया, स्वप्नम्, भयम्, शोकम्, विषादम्, मदम् एव, च,
न, विमुञ्चति, दुर्मेधाः, धृति:, सा, पार्थ, तामसी।।35।।

Gita 18.35

Yya, swapnam’, bhayam’, shokam’, vishaadm’, madam’, ev, ch,
Na, vimunchati, durmedhaH, dhrtiH, saa, paarth, taamsi ||35||

Translation: (Paarth) Oh Paarth! (durmedhaH) a person of mean nature (yya) which (swapnam’) sleep (bhayam’) fear (shokam’) worry (ch) and (vishaadm’) misery and (madam’) intoxication (ev) also (na, vimunchati) does not give up (saa) that (dhrtiH) firmness in bhakti (taamsi) is Tamsi. (35)

Translation: Oh Paarth! Sleep, fear, worry and misery and also intoxication, which a person of mean nature does not give up – that firmness in bhakti/steadfastness is Tamsi.