After three days - These three days are probably to be thus understood: As soon as Joshua took the command of the army, he sent the spies to ascertain the state of Jericho; as we have seen Joshua 1:12. They returned at the end of three days, or rather on the third day, and made their report. It was at this time, immediately on the return of the spies, that he made the proclamation mentioned here; in consequence of which the people immediately struck their tents, and marched forward to Jordan.
These days (Joshua 1:11 note) were no doubt occupied in preparations of various kinds. The host consisted not of armed men only, but of women and children also; and many arrangements would be necessary before they actually advanced into a hostile country.