Ātma-Saṃyama Yoga · Verse 23
तं विद्यादुःखसंयोगवियोगं योगसञ्ज्ञितम् | स निश्चयेन योक्तव्यो योगोऽनिर्विण्णचेतसा
taṃ vidyād duḥkha-saṃyoga-viyogaṃ yoga-saṃjñitam | sa niścayena yoktavyo yogo 'nirviṇṇa-cetasā
This should be known as yoga: the dissolution of contact with suffering. This yoga should be practiced with determination and with mind undiscouraged.
Operational definition of yoga: duḥkha-saṃyoga-viyoga — separation from contact with suffering. It is not that suffering disappears, but that the yogi is no longer joined (saṃyoga) to it.
Practice: niścayena (with firm resolution), anirviṇṇa-cetasā (with mind undecayed, undiscouraged). The path requires persistence.