John Gill Commentary Numbers 31:26

"Take the sum of the prey that was taken, both of man and of beast, thou, and Eleazar the priest, and the heads of the fathers` [houses] of the congregation;" — Numbers 31:26 (ASV)

Take the sum of the prey that was taken, both of man and
beast
The number of the females that were taken captive and spared, and of the cattle, the sheep, oxen, and asses:

you, and Eleazar the priest, and the chief fathers of the
congregation ;
who were all men of authority and character, and fit to be employed in such service, and of whose capacity and fidelity there could be no doubt.