The guṇas are the strands of which prakṛti is woven. Their changing proportions account for the variety of things and of minds: sattva is light and calm, rajas passionate and restless, tamas heavy and dull. The Bhagavad Gītā analyses food, faith, action and knowledge by the guṇas, and teaches going beyond all three.
Guṇas
The three qualities of nature: sattva, clarity; rajas, activity; and tamas, inertia.
Also: Gunas, three qualities