What does the Bible say about why believers get sick?

In John 9:3, Jesus explains that the blind man's condition was not due to sin but for the works of God to be made manifest. This indicates that sickness can serve a divine purpose, showcasing God's glory and power. Sickness in the lives of believers can be seen as an opportunity for God to display His grace and bring about spiritual growth and reliance on Him. Romans 5:3 reminds us that tribulations produce perseverance and character, demonstrating that God uses illness to refine His people and increase their dependence on His mercy.