Jesus rejects both possibilities. Although suffering may be the result of personal sin (John 5:14) or of the sin of parents (or ancestors to the 3rd and 4th generation), this is not always the case. Suffering is not always the result of our sin. It often occurs as a result of natural happenings. God has set in motion a series of natural laws to give order and continuance to creation and much suffering comes in the ordinary course of things. It has a cause which is only natural. However, all suffering, even that which is a result of natural happenings, can ultimately be traced back to the fall of man and the resulting curse caused by his sin (Gen 3:16-19). So in the broad sense, all suffering is the result of sin. And Jesus is the Healer of all suffering by being the Healer of its ultimate cause.

John 5:14  Later Jesus found him at the temple and said to him, “See, you are well again. Stop sinning or something worse may happen to you.”

Genesis 3:16-19  To the woman he said, “I will greatly increase your pains in childbearing; with pain you will give birth to children. Your desire will be for your husband, and he will rule over you.”  To Adam he said, “Because you listened to your wife and ate from the tree about which I commanded you, ‘You must not eat of it,’ “Cursed is the ground because of you; through painful toil you will eat of it all the days of your life.  It will produce thorns and thistles for you, and you will eat the plants of the field.  By the sweat of your brow you will eat your food until you return to the ground, since from it you were taken; for dust you are and to dust you will return.”

Note that the disciples asked for Jesus to tell them the why of the man’s suffering and He instead told them its purpose. Note also that the man is not deaf; he has probably heard everything that was said.

purpose = to manifest the “work” of God. Notice that what we consider to be a miracle is considered by God to just be some work that He does. The suffering of man enables the following to make visible the glory of God in these ways:

• God, Himself – Our suffering creates an opportunity for God to change the natural course of events and heal or deliver in such a manner that it is obvious that He has done it.
• the sufferer – Our suffering enables us to show the glory of God to others. The story is told of an old saint who was dying in pain and agony. He sent for his family saying, “Come and see how a Christian can die.” (Barclay) The story is also told of the soldier who was guarding the Christians as they were being killed in the arena by the wild beasts. Upon witnessing the calm reserve and assurance of these saints, the soldier put down his weapons and stepped in line to die with them, stating that he wanted what they had. The way we handle our suffering is the most powerful of all testimonies to the lost.
• others – Suffering enables others to display the glory of God by ministering to the sufferer. As Barclay points out, when we help a fellow man, we show forth the glory of God because we are showing what He is like. When we see others suffering, it is our opportunity to help them as best we can — just like Jesus would do.