What does John 9:2 mean?

In the disciples' culture, sickness and suffering were often seen as a punishment for sin. It was assumed that those who suffered "deserved it;" or at least someone in their family did. That this man was born blind leaves the disciples with only two options: either the man somehow sinned before his birth or he is being punished for something his parents did.

Jesus will directly counter this mistake (John 9:3). Personal suffering is not necessarily linked to one's own personal sin. In a broad sense, all suffering is a result of sin. We suffer the aftershocks of the fall of man through Adam (Romans 5:12). Also, most suffering we experience in this world is primarily the result of human sin. Everything from political unrest to poverty to hunger are grounded in humanity rejecting their created purpose. But, as this man's example shows, not all suffering is directly deserved, in and of itself.

In other words, not everything that happens to a person happens because they did something wrong. Hardship, suffering, persecution, and pain are not surefire signs of divine retribution. This directly counters the idea of karma, which suggests that suffering is, in some way, the suffering person's fault.