The first chapter of Patanjali’s Yoga Sutras is about enlightenment - Samadhi Pada.

Samadhi (समाधि, Samādhi) = Enlightenment
Pada (पाद, Pāda) = ChapterThe first chapter of the Yoga Sutra by Patanjali


Sentence 13

tatra sthitau yatno-'bhyasah ||13||

तत्र स्थितौ यत्नोऽभ्यासः ॥१३॥

tatra sthitau yatno-'bhyāsaḥ ॥13॥

Assiduousness means resolutely adhering to one’s practice of yoga. ||13||

tatra = (adv.) here; there; so that
sthitau = (nom. du. m./acc. du. m.) resolutely; continuously; constantly;
yatna = (nom. sg. m.) effort; practice
abhyāsaḥ = (nom. sg. m. from abhyāsa) cheerfulness; assiduousness