Yoga Sutras of Patanjali · 2.1

तपःस्वाध्यायेश्वरप्रणिधानानि क्रियायोगः ॥१॥

tapaḥ-svādhyāyeśvarapraṇidhānāni kriyāyogaḥ

Austerity, self-study, and surrender to the Lord — these together constitute Kriya Yoga, the yoga of practice.

— Yoga Sutras of Patanjali 2.1

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).