Yoga Sutras of Patanjali translated by Yogi Kalinath - Chapter 3, Verse 5
Pada 3, Sutra 5
Through mastery of Samyamah comes the light of insight.
The pure unblemished nature of mind is light, the light of pure awareness. By first constraining the mind so it is not distracted and dissipated, it starts becoming aware of awareness itself. Awareness becomes integrated dissolving into awareness itself, the illuminating insight of direct perception.
Awareness of awareness is the foundation of discernment.