John 9:12-31 King James Version (KJV)
12 Then said they unto him, Where is he? He said, I know not.
13 They brought to the Pharisees him that aforetime was blind.
14 And it was the sabbath day when Jesus made the clay, and opened his eyes.
15 Then again the Pharisees also asked him how he had received his sight. He said unto them, He put clay upon mine eyes, and I washed, and do see.
In this passage, the man was blind from birth, he was also a beggar who had the routine of waiting by the gates of the temple for gifts from the worshipers.
In those days it was commonly thought that a sickness was a result of sin and that if the parents committed a sin, it was transferred to the child of those parents. But Jesus rejected this idea.
In this particular situation, God allowed the man to be born blind so that Jesus could heal him and reveal the works of God through the man Jesus Christ so that people would know His healing power.
Back in those days, mixing saliva with clay was a common practice used for eye infections. Jesus used this opportunity to show the man exercising his faith in Jesus Christ.
The apostle John emphasized that the name of Siloam meant sent. So, the man "went and washed and came back seeing".
The crowd in the area, including this man's own parents knew who this man was and they also knew that Jesus had put clay on his eyes and sent him to the pool of Siloam to wash his eyes out, but everybody denied knowing anything about the facts of what happened.
"This is an accurate picture of many today. The truths of Christianity have been proclaimed to them—perhaps by parents, friends, or the church. Intellectually, they know and even believe these truths, but they will not admit them. They are afraid to acknowledge Christ for fear of the consequences." (Martin G. Collins)