Comentario sobre Números 31:36

AND THE HALF, WHICH WAS THE PORTION OF THEM THAT WENT OUT TO WAR, WAS IN NUMBER etc. Scripture had to enumerate [the spoil] in such detail, mentioning how much was the half [of these who went to war] and how much was the tribute [given to the priests and Levites, although both these figures can be worked out from the total figures mentioned], in order to inform us that from the day that they took this booty until they counted and halved it, set aside the tribute and gave it to Eleazar the priest, not one of all this great herd died. This was a miracle. This is also [the reason why Scripture mentions] the half [given] to the congregation [of Israel who did not fight, and the amount that they gave] to the Levites.¹¹³Verses 42-47.

ותהי המחצה, “the half amounted to, etc.” Nachmanides writes that there was a need to state what appears as obvious to the casual reader of the text. The Torah wanted to point out that since the day the loot was captured, and subsequently counted, and still later distributed, there had been zero shrinkage. None of the animals had died, and none of the silver, gold, etc., had disappeared. The levy was also handed over in accordance with the percentages specified by the Torah.