"He spat on the ground and made mud with the saliva" (John 9:6).
Warning: You may never look at spitting the same way.
Three times in the Holy Gospel Jesus spits, and each time in order to heal. Mark records two occasions (Mark 7:31-37 and 8:22-26) and John another (John 9:1-7). John alone uses the noun "saliva" - a word that almost seems to be trying to spell "salvation."
God is omnipotent, but there was something He could not do. Prior to the Incarnation He could not spit. In the Person of the Son, God put on our human flesh and blood - and saliva.
Think of it this way: The Word became flesh and spit among us (cf. John 1:14). When you come to these healings in which Christ uses His spit, think deeply about the Incarnation and rejoice that God became man for us!
But wouldn't you know: The same Incarnation that enabled the Lord to spit, also enabled Him to be spit upon.
"Then they spit in His face..." (Matt. 26:67). See the prophecy of this in Isaiah 50:6.
This is nearly unspeakable. The one true God and Creator of all is spit upon by His creatures! And yet we speak it and preach it and proclaim this Gospel of the depths to which the Lord God humbled Himself for us and for our salvation!