This verse confirms that the conquest of Canaan was not fully completed even when the book of Joshua was formally written down. Most likely an editor, at some stage in the final composition of the book, inserted this comment. This comment is thus not predictive but a later statement about the failure of these tribes. The results of this failure would plague Israel in the far future. David’s son Absalom was born to a Geshurite princess (2 Samuel 3:3) and he would take refuge in that region when he rebelled against his father (2 Samuel 13:37–38; 2 Samuel 14:23, 2 Samuel 14:32). Maacah would also send 1,000 men to be part of the coalition against David (2 Samuel 10:6, 2 Samuel 10:8).
13 Yet the people of Israel did not drive out the Geshurites or the Maacathites, but Geshur and Maacath dwell in the midst of Israel to this day.