Moses uses a question to teach his audience. His previous instruction of, "Do not say" requires a negative answer to this question. You can translate this as a statement. Alternate translation: "No person can go down and enter the place where the spirits of dead persons are." (See: [[rc://en/ta/man/translate/figs-rquestion]])
All those who have died. This expression describes all dead people together in the underworld. To be brought up from among them is to become alive again.