Bhagavad Gita · 17.14

देवद्विजगुरुप्राज्ञपूजनं शौचमार्जवम्।ब्रह्मचर्यमहिंसा च शारीरं तप उच्यते॥

deva-dvija-guru-prājña-pūjanaṁ śhaucham ārjavam brahmacharyam ahiṁsā cha śhārīraṁ tapa uchyate

Worship of the gods, the twice-born, the teachers, and the wise; cleanliness, straightforwardness, celibacy, and non-violence — these are called austerity of the body.

— Bhagavad Gita 17.14

Source: Sacred-Texts.com (Sanskrit) + Bhagavad-Gita.io (translations)