Jesus was asked to heal a blind man, and he wrote something in the dust, spit on it, made clay and fitted it to the blind man's eyes. What did he write?
You seem to be combining two different stories, both from the Gospel of John. Jesus writes in the dust when the Pharisees bring to him a woman taken in adultery and ask him what they should do with her. “Jesus bent down and wrote with his finger on the ground. And as they continued to ask him he stood up and said to them, ‘Let him who is without sin among you be the first to throw a stone at her’” (Jn. 8:6-7).
No one, of course, can say with any certainty what Jesus wrote on the ground. One interpretation is that he wrote in the dust the sins of the men around him—reminders of why they were not perfect enough in their own choices to punish another for hers. It's also possible that Jesus was referencing Jeremiah 17:13: “O Lord, the hope of Israel ... those who turn away from thee shall be written in the earth, for they have forsaken the Lord, the fountain of living water.” In other words, without the “living water” of our Christ Presence—our innate, infinitely loving Oneness with God—we are no more than the dust from which our physical bodies are formed.
It is shortly after that, in John 9, that Jesus encounters a man blind from birth. “He spat on the ground and made clay of the spittle and anointed the man's eyes with the clay, saying to him, “Go, wash in the pool of Siloam.” ... So he went and washed and came back seeing (Jn. 9:6-7).” Certainly the healing power is not in the dirt, nor in the spittle. Jesus heals in many different ways in the course of his ministry. Sometimes physical contact is involved, sometimes not. Sometimes the person is present, sometimes distant. I think what's significant is that Jesus was able to intuitively know just how each person needed to “receive” a healing in order to believe—because, as he taught over and over again, it is the belief of the afflicted person that allows the healing to happen.