Devarim 2:14: And the days when we went from Kadesh barnea, until we crossed the brook of Zered, numbered thirty eight years, until all the generation of the men of war expired from the midst of the camp, just as the L-rd swore to them. Also the hand of the L-rd was upon them, to destroy them from the midst of the camp, until they were consumed.
Rashi: "[Also the hand of the L-rd] was against them": to quickly destroy them within a period of forty years, so that they would not cause their children to tarry any longer in the desert.
