Job 36:8

And if they be bound in fetters, and be holden in cords of affliction;

The verse falls within Elihu's speeches, which span Job 32-37. It belongs to the book's treatment of human suffering. It pictures sufferers as bound and constrained, as if held in fetters and cords of affliction.

Affliction serves as God's discipline to bring people's actions and excessive sins to their attention, exposing their wrongdoing and showing them what they must change. Suffering, including sickness, is God's call to accept discipline, receive instruction, and turn from sin and wrongdoing. The verses that follow promise that those who obey and serve God will spend their days in prosperity and their years in pleasure.

Affliction by itself does not prove a person is under God's displeasure. God may chasten those He loves. Suffering borne for His sake can bring glory to Him and good to the sufferer when met with trust.