Yoga Sutras of Patanjali · 4.13

ते व्यक्तसूक्ष्मा गुणात्मानः॥१३॥

te vyaktasūkṣmā guṇātmānaḥ

These dharmas — past, present, and future — are essentially of the three gunas. They are sometimes manifest, sometimes subtle.

— Yoga Sutras of Patanjali 4.13

Source: Sanskrit attributed to Patanjali (c. 2nd century BCE – 4th century CE). Public-domain English readings drawn from Swami Vivekananda's 'Raja Yoga' (1896) and Charles Johnston's 'The Yoga Sutras of Patanjali' (1912).