The phrase "the whole community" emphasizes that every person who was a part of "the people of Israel" was present, without exception. (See: [[rc://en/ta/man/translate/figs-doublet]])
This is a gentle way to say that Aaron must die. It means that it is time for Aaron to die and for his spirit to go to the place where his ancestors are. AT: "Aaron must die" (See: [[rc://en/ta/man/translate/figs-euphemism]])