275. Mum’s the Word: The prohibition against a kohein with a defect serving

A kohein who has a physical blemish, called a “mum” in Hebrew, may not serve in the Temple. The blemish referred to here is one of a permanent nature, for example a disfigured limb.

The reason underlying this mitzvah is that human beings are kind of shallow and superficial. (Why do you think elected officials tend to be taller than average? And don’t kid yourself that looks don’t play a role in elections – see the famous Kennedy vs. Nixon debate in the 1960 election.) If a kohein has some form of disfigurement, most people are incapable of looking past that to see his real value as a person. They would be distracted by the fact that the kohein is a little person or an albino or a conjoined twin and that would have a negative impact on the kohein’s ability to serve. It’s no fault of the kohein’s but most people simply can’t get over such differences and they would disparage the service because they cannot appreciate the messenger. They must be educated but in the middle of the Temple service isn’t the place for it.

Only visible defects disqualify a kohein from serving. A problem with an internal organ that cannot be seen is not a problem. Even if the kohein had an internal organ removed, he may serve.

This mitzvah applies in Temple times. It is discussed in the Talmud in tractate Bechoros on pages 43a-45b. It is codified in the Mishneh Torah in the sixth chapter of Hilchos Biyas HaMikdash. It is #70 of the 365 negative mitzvos in the Rambam’s Sefer HaMitzvos.