Bhagavad Gītā Chapter Six verse 23

taṃ vidyād duḥkhasaṃyogaviyogaṃ yogasaṃjñitam |
sa niścayena yoktavyo yogo ’nirviṇṇacetasā ||

duḥkha - suffering, pain, sorrowfulsaṃyoga - conjunctionyoga - the act of yokingviyoga - unyoking, separation