Moses repeats the same command both positively and negatively to emphasize the importance of remembering. The command is plural. Alternate translation: "Be careful to remember" (See: [[rc://en/ta/man/translate/figs-doublet]] and [[rc://en/ta/man/translate/figs-you]])
Here "you" refers to the Israelites that are present with Moses and also the Israelites of the previous generation. (See: [[rc://en/ta/man/translate/figs-you]])