Bhagwad Gita
Chapter 6, Verse 23
तं विद्याद् दुःखसंयोगवियोगं योगसंज्ञितम्।
स निश्चयेन योक्तव्यो योगोऽनिर्विण्णचेतसा।।6.23।।
Let this be known by the name of Yoga, the severance from union with pain. This Yoga should be practiced with determination and with an undespairing mind.