The Israelites had planted crops and were augmenting their meals of manna with fresh produce from the land. They had begun to put down modest roots. As a matter of fact, the tribes of Reuben, Gad and Manasseh had petitioned Moses to make their permanent dwelling place on this side of the Jordan, and God had permitted them to do so.

So, when Joshua sent out word that they were leaving in three days, it was very short notice for a move of that magnitude.