Charles Ellicott Commentary Deuteronomy 2:14

"And the days in which we came from Kadesh-barnea, until we were come over the brook Zered, were thirty and eight years; until all the generation of the men of war were consumed from the midst of the camp, as Jehovah sware unto them." — Deuteronomy 2:14 (ASV)

Until we were come over the brook Zered. —The root zârad in Chaldee means to prune. The name “Zered” signifies the luxuriant foliage and the young shoots, especially of the willow, which are cut off with the knife, as the Targum interprets it (Numbers 21:12). Probably the valley was so named from the “willows of the brook” which grew there. But it was the “valley of pruning” to the “vine” which God had “brought out of Egypt” in another sense. The last of the fruitless branches was here taken away, and the vine purged, that it might bring forth more fruit.

Thirty and eight years; until all ... men of war were wasted out from among the host. —The census did not take place until some months later. A plague intervened, which cut off twenty-four thousand. The observation that at the brook Zered all the men of the older generation were wasted out of the host indicates an intimate knowledge of the incidents of the exodus. But it is quite natural to suppose that, as the survivors of that generation became fewer, those who remained would become marked men.

Every man of the twelve tribes (excluding Levi?) who passed the census at Sinai was doomed. The fortieth year of the exodus had more than half expired when they came to the brook Zered. All who remained alive in that year knew that they had a short time to live. Probably more notice was taken of the last few deaths than of all the rest of the six hundred thousand put together.