Yoga Sūtra Chapter Two verse 43

कायेन्द्रियसिद्धिरशुद्धिक्षयात् तपसः ॥४३॥

kāya-indriya-siddhiḥ aśuddhi-kṣayāt-tapasaḥ ||43||

From self-discipline, impurities diminish
and accomplishment in the body and senses.

kāya - the bodyindriya - faculty of sense; sense; organ of sensesiddhi - accomplishment, performance, fulfilment, attainment, successaśuddhi - impuritykṣaya - diminish, wasting or wearing awaytapas - to heat; religious austerity; self-discipline; pain, suffering

Commentaries and Reflections

T Krishnamacharya:

Tapas
– Good, limited food
– The ability to listen
– Sharpening the senses
– Building resistance to Dvaṃdva