Patanjali Yoga Sutra 1.13

Sanskrit Sutra

तत्र स्थितौ यत्नोऽभ्यासः॥१३॥

Swami Vivekananda's translation

Continuous struggle to keep them (the Vrittis) perfectly restrained is practice.

Vyasa Bhashya (Sanskrit)

तत्र स्थितौ यत्नाऽभ्यासः ॥ १३ ॥

चित्तस्यावृत्तिकस्य प्रशान्तवाहिता स्थितिः। तदर्थः प्रयत्नो वीर्यमुत्साहः। तत्संपिपादयिषया तत्साधनानुष्ठानमभ्यासः ॥ १३ ॥

Vyasa Bhashya (English Translation)

Among these, practice (abhyasa) is the effort to secure steadiness (sthiti). || 13 || Steadiness is the calm flow of the mind devoid of fluctuations (vrittis). The effort, energy, and enthusiasm for that purpose - the performance of practices with the desire to accomplish it - is called practice (abhyasa).

Chapter link: Yoga Sutra Chapter 1