Though Israel turned back from invading Canaan, they still ran afoul of surrounding nations:  Edom, Arad, Amorites, Bashan (Num 20-21).  Israel was on the march, and her movements threatened the status quo of the nations. This is understandable -- the Negev may have been wild, but it was not empty, and the resident tribes had recognized borders.  Having a couple million people wandering through this area was like letting an elephant into a teashop.  Israel had no intention of destroying Edom, but the rest of the peoples mentioned were fair game.  These conflicts may be considered a warmup for the actual conquest of Canaan under Joshua.