מדרש על במדבר 26:1

And at that time, after the pestilence was over, the Lord said unto Moses and Eleazar, the ‎priest, saying: Number ye the heads of the entire congregation of the children of Israel from ‎twenty years and upwards, all those that went forth in the army; and Moses and Eleazar ‎numbered all the children of Israel according to their families, and the number of all Israel was ‎seven hundred thousand and seven hundred and thirty.‎‏ ‏And of the number of the children of ‎Levi from one month and upwards was twenty three-thousand; and there was not among ‎those numbers one man of those that were numbered by Moses and Aaron in the wilderness, ‎for the Lord had said concerning them, that they would all die in the wilderness, and thus not ‎one remained of them, save Caleb, the son of Jephunneh, and Joshua, the son of Nun. After ‎this the Lord spoke unto Moses, saying: Speak unto the children of Israel, that they avenge the ‎cause of their brethren.‎‏ ‏And Moses did so, and the children of Israel selected twelve thousand ‎men from their midst, one thousand from each tribe, and they went unto Midian.‎‏ ‏And they ‎fought against Midian, and they slew every male, and the five princes of Moab and Balaam, ‎the son of Beor, they slew likewise with the sword.‎‏ ‏And the children of Israel captured all the ‎wives of the Midianites, and their children, and their cattle, and alf belonging unto them, and ‎they took all the spoil and all the captives, and they brought them unto Moses and Eleazar, ‎into the plain of Moab.‎‏ ‏And Moses and Eleazar, and all the princes of the congregation went ‎forth to meet them with joy, and they divided all the spoil of Midian, and thus the children of ‎Israel avenged on Midian the cause of their brethren, the children of Israel.‎

7 (Numb. 26:1-2) “And it came to pass after the plague [that the Lord said unto Moses and unto Elazar ben Aaron the priest, saying,] ‘Take a census’”: Every time that they fell, they were required to be numbered. The matter is comparable to the wolf who went into the midst of the flock. The owner of the flock was obliged to count them to know how many were missing. Another interpretation (of Numb. 26:2): Why did he count them [here]? The matter is comparable to a shepherd to whom the householder has delivered a flock after numbering them. [After] he has fulfilled his guardianship, when he returns them, it is necessary for them to be numbered. Thus when Israel went out from Egypt the Holy One, blessed be He, delivered them to Moses after numbering [them], as stated (in Numb. 1:1-2), “Then the Lord spoke unto Moses in the Sinai desert …, ‘Take a census […].’” [Likewise] (in Exod. 12:37), “Then the Children of Israel traveled from Ramases to Succoth, about six hundred thousand men on foot.” Ergo, he received them with a numbering in Egypt. [So when] he was about to pass away from the world in the Plains of Moab (after completing his guardianship), he returned them with a numbering.