If a person gets sick, does that mean that they have sinned?

There are many people who believe that God works the same way karma does.  If something bad happens to someone it is because they messed up in some way.  However, this is not how God operates; it is from a human perspective.  In John 9 Jesus and His disciples encountered a man blind from birth.  The disciples, thinking as most do, wondered who sinned to cause this, the man or his parents.  How could the man have sinned before he was born to cause his blindness!  Jesus told them and tells us that no one sinned to cause his condition, but it is for the glory of God.  We need to remember that even though things seem bad, God is able to use these situations to guide others to Him and bring glory to His name.