Bhagavad Gita · Chapter 14: The Three Qualities of Nature
Bhagavad Gita 14.5
सत्त्वं रजस्तम इति गुणाः प्रकृतिसंभवाः ।
निबध्नन्ति महाबाहो देहे देहिनमव्ययम् ॥
sattvaṃ rajastama iti guṇāḥ prakṛtisaṃbhavāḥ | nibadhnanti mahābāho dehe dehinamavyayam ||
Clarity, passion, and inertia: these three qualities, born of nature, bind the imperishable embodied self to the body, mighty-armed Arjuna.
Modern context
The three gunas are named: sattva, clarity; rajas, passion or restless energy; tamas, inertia or heaviness. Every mind, every food, every activity, every moment has some mix of the three. A calm morning is sattvic; a rushed, ambitious day is rajasic; a dull, sleepy afternoon is tamasic. Most importantly, all three bind. Even the pleasant clarity of sattva can become a cage if we cling to it.