ויקרא טז:יז פירוש: רבנו בחיי וחזקוני

.וכל אדם, “not any human being, as they were not allowed into those precincts, but this is a warning to other priests not to be in these holy precincts during the period that the High Priest performs these functions.

לא יהיה באהל מועד, “he must not be within the precincts of the Tent of meeting;” the reason why they were forbidden to be there was so that they would not become suddenly ritually impure, as the priest officiating would not be able to atone on their behalf on the same day.