“When He had said these things, He spat on the ground and made clay with the saliva; and He anointed the eyes of the blind man with the clay.” John 9:6
A metaphor for holy Baptism. The dirt moistened with spittle and the washing were means of grace. Yet there was something for the man to do—he had to go and wash. It wasn’t the washing that did it; it was the word of the Son of God connected with the washing.