यया स्वप्नं भयं शोकं विषादं मदमेव च।न विमुञ्चति दुर्मेधा धृतिः सा पार्थ तामसी।।18.35।।
yayā svapnaṁ bhayaṁ śhokaṁ viṣhādaṁ madam eva cha na vimuñchati durmedhā dhṛitiḥ sā pārtha tāmasī
That firmness, O Arjuna, by which a stupid man does not abandon sleep, fear, grief, despair, and conceit, is Tamasic.