St John Chrysostom writes:
For since they heard that God made man, taking the dust of the earth, for this reason in like manner He also fashioned (clay). Indeed, for Him to have said, "I am the One Who took dust from the earth and fashioned the man" would have been arduous to bear and repugnant to His hearers. But when this was shown in actual deed, it no longer stood in the way. Wherefore by taking earth and mixing it with spittle, thus His hidden glory was made manifest. For it was no small glory that He should be believed to be the Maker of creation.