Many religious rituals involve a washing or a bathing. This washing/bathing symbolically connects the physical cleanliness with a spiritual/moral purity. Washing is a powerful symbol for a number of reasons and Christianity uses this symbol in baptism, in telling the story of Jesus' last supper and even at his trial. When I was working for the Catholic Church I would help the priest symbolically wash his hands before celebrating communion and even as a minister today, I put hand sanitizer on my hands prior to communion.
While the Church has long understood the validity of the sacrament does not depend upon the moral character of the minister (which is why I will not re-baptize you) we still hold onto the connection between physical and moral purity.
Dr. Thalma Lobel writes in her Sensation: The New Science of Physical Intelligence about a study about bathing and honesty. Here is the set up:
People were given a test and when the time was up, the answer sheet was given to each person to "check their answers". The people were to use the answer sheet to mark on their own pages the number of incorrect answers they gave. They found that some people used the answer sheet and changed some of their original answers and gave themselves a better score.
Some in the group were asked to take a shower prior to the test and others were not. The assumption was that those who took the shower before the test would be physically clean and thus influenced to be morally clean when it came test time. However the study showed that those who were more likely to lie or cheat were those who took a shower prior to the test.
The reason? The researchers suggest that those who took the bath "felt clean" (both physically and morally) and thus felt they had a little more "room to get dirty".
Clergy are constantly in a position of being physically clean. We go into hospitals and must wash a our hands. We perform rituals that require a physical washing as a part of the ritual. We are expected to have clean clothes and look "professional' and "put together", and if not then we question the if the man who looks disheveled is a very good clergy person. Clergy expectation/stereotypes involve descriptors like being "squeaky clean", using "clean" never "foul" language", and avoiding the "dirty side" of life (such as smoking and drinking and rated R movies that deal with the macabre). Could these expectations of clean clergy ironically, contribute to clergy feeling more like we have room to "get a little dirty"?
Maybe this is in part why Jesus was not in favor of his disciples washing their hands before eating?