While walking in Jerusalem, the disciples see a man born blind and ask Jesus why the man was born blind (verse 1-2). Judaism sometimes connected sin and illness. The reason for this is a strong belief that God judges sin with illness. The three friends in the book of Job is the classic example of the belief that extreme illness and suffering is the result of sin. For example, when Miriam rebelled against Moses, she was struck with leprosy. The same is true for Uzziah, a king who violated the law. When Hezekiah became ill he took it as a sign of divine disfavor.
In addition to suffering for your own sins, there are a number of texts in the Hebrew Bible that indicate some sins will be punished for several generations. Idolatry, for example, carried a punishment for three more generations. Frequently kings were not directly punished for their rebellion, but their sons or grandsons are killed, ending their line.
Another possibility for a man born blind is that he sinned in the womb. For most of us, the idea of a prenatal sin is difficult to understand. The rabbinic Genesis Rabbah suggests that Esau was “hated” and Jacob “loved” because he had committed sin in the womb.
“R. Bekehja said in the name of R. Levi: “When she [Rebecca] walked past synagogues and houses of instruction, Jacob struggled to get out, in accordance with Jer 1:5: ‘Before I formed you in your mother’s womb I knew you.’ And when she passed idol temples Esau ran and struggled to get out, in accordance with Ps 58:4, ‘The godless go astray from the womb’” (Gen. Rab. 63; Text cited is from Beasley-Murray, John, Second Edition, 154)
Jesus denies a “universal principle” that sin and sickness are connected. There may be cases, (Miriam, Paul’s comments to the Corinthians about their abuse of the Lord’s supper), but not all sickness can be connected to a specific sin. Generally, alcohol abuse often leads to a natural physical consequence; this natural result hardly a judgment of God!
Jesus rejects the normal explanations for the blindness of the man. He was born blind so that God’s power might be displayed in him (John 9:3-5). The blind were considered unclean and were always excluded from Temple worship. Since they are blind, they cannot know when they might contact some unclean thing, therefore they could never be allowed to go up to the Temple to worship.
Jesus indicates that he will not always be in the world. Since he is the light of the world, it is the time to do the work of God.
Jesus already declared he is the “light of the world” (John 8:12). Now he will demonstrate this by illuminating the darkness of the blind man. John 9 is connected to the previous via “the light of the world.”