Ps 38:3 Because of your anger, my whole body is sick; my health is broken because of my sins.
Everyone suffers illness, sometimes minor, and sometime catastrophic. We live in a world full of germs and viruses, so sometimes an illness may be from exposure to “worldly” things. However, sometimes our sins affect our health.
David felt his anguish as a judgement from God. In certain circumstances, God will allow a physical or mental side effect of our sin. It is extremely difficult to discern the origin of the problem, because not all sickness is caused by sin.
When a cold or something much worse attacks us we tend to believe that if God wants to heal us, he will. I have seen Christians suffer because they are “waiting on the Lord to heal them”. Whether it was a stomach virus or a respiratory infection, if I stop and take care of myself then I am better equipped to help others.
Everything in life has consequences; some good and some bad. Sometimes God allows sickness in order to bring us back to him. He wants our focus on him not on the world. When we repent, he forgives and heals us. But he never promised to undo all of sin’s earthly consequences. Remember, sometimes Christians get sick, so pray and ask God to show the cause. The solution may be as simple as taking a vitamin or as difficult as breaking an old habit. Whatever the consequences God will guide us to the solution as we draw closer to him.