Patanjali Yoga Sutra 2.46

Asana is a seat that is steady and easeful.

स्थिरसुखमासनम् ॥

sthira-sukham asanam ||

Asana is a seat that is steady and easeful.

In Patanjali, asana is first a stable seat for attention, not a performance. Pain-as-virtue is not this sutra. After trauma, steady and easeful includes the right to stand up and leave.