When we think of a clergyperson in our culture today, we typically see them as someone who is good at being good. It makes perfect sense. In general society, the professional is the expert. She is BETTER than those she serves. This is (thank God) true for brain surgeons, taxidermists, dental workers, and teachers.
Two things come to mind - first, we all have feet of clay, and second, they say that the ground is level at the foot of the cross.