“Hashem said to Moshe: Speak to the Kohanim, the sons of Aharon, and say to them: None shall defile himself for any [dead] person among his kin” LEVITICUS 21:1 (The Israel Bible™)
While the entire Nation of Israel is commanded to maintain a certain level of holiness, the Kohanim were held to an even higher standard. For example, a priest may not become ritually impure through contact with a dead body. Therefore, he may not participate in the burial of anyone other than his immediate relatives. However, Rashi teaches that there is an exception to this rule. If there is no one else to bury the person, then even the Kohen Gadol is obligated to perform the burial, even if the deceased is not “among his kin.” This is particularly striking, since under normal circumstances, unlike ordinary Kohanim, the Kohen Gadol may not participate in the burial of even his closest relatives. In this way, the Bible teaches that an elevated status must not make one oblivious to the needs of people. On the contrary, it is the obligation of those with heightened responsibility to see to it that everyone is taken care of, even at the expense of their own personal state of holiness.