Pass through the midst of the camp, and command the people, saying, Prepare food; for within three days you are to pass over this Jordan, to go in to possess the land, which Yahweh your God gives you to possess it.
(2) Also, the three days mentioned in this verse had already been preceded by the three days mentioned in  Joshua 23:2.  No discerning student of ancient documents can be upset by a minor difficulty such as this.  We see no good reason for not accepting Plummer's explanation: