In this class (Class 8), we discuss Yoga Sūtra 1.19–1.20, along with Edwin Bryant's commentary on these sūtras (pp. 73-78 of Edwin Bryant's book The Yoga Sūtras of Patañjali).

Link to Swami Medhananda's article, "Yogic Mindfulness: Hariharānanda Āraṇya's Quasi-Buddhistic Interpretation of Smṛti in Patañjali's Yogasūtra I.20"