BHAGAVAD GITA · CHAPTER 18, VERSE 39

Bhagavad Gita 18.39

यदग्रे चानुबन्धे च सुखं मोहनमात्मनः। निद्रालस्यप्रमादोत्थं तत्तामसमुदाहृतम्॥

That happiness which deludes the self both in the beginning and in the end, arising from sleep, indolence, and negligence, is declared to be Tamasic.