"As he said this, 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 poor of Siloam' (which means Sent). So he went and washed and came back seeing."
What I find most remarkable about this passage is how Jesus uses such mundane materials -- water, dirt, and spit -- to effect a miracle and enable a man born blind to see. He certainly doesn't have to -- He is God, He can do whatever He wants, He can perform miracles merely by commanding them. But in this case, for whatever reason, Jesus chooses to work through the humble medium of matter.
I find it helpful to remember this sometimes when it seems hard to believe that God would actually convey grace through the everyday elements -- water, oil, bread, wine -- of the sacraments of the Church.
I think there's an almost Gnostic tendency these days to feel that all things spiritual must somehow be kept separate from the lowly material realm. But to hold this belief consistently would be to resist the truth not only of certain of Jesus' miracles, but also of the mystery at the very center of the Christian faith: that God effected our salvation by becoming flesh and dying on a cross.