In John 9 is a powerful story about a young man that was blind from birth.  One of the first things we learn is that not all suffering is the direct result of a specific sin.  Though sin always leads to some form of suffering, not all suffering is a result of sin. In this case, Brother Marty points out that this man had suffered from blindness for the sole purpose of being a vessel for God to display his goodness, mercy, and power.