You shall send a thousand from each of the tribes of Israel to the war.”
Of every tribe a thousand,.... So that the whole number of those that were armed were 12,000 as after given: throughout all the tribes of Israel; this is observed, as Jarchi thinks, to comprehend the tribe of Levi, which in some cases was left out of the account: shall ye send to the war; to fight with Midian.
Num 31:3-6 To carry out this revenge, Moses had 1000 men of each tribe delivered (ימּסרוּ, see at Num 31:16) from the families (alaphim, see Num 1:16) of the tribes, and equipped for war; and these he sent to the army (into the war) along with Phinehas the son of Eleazar the high priest, who carried the holy vessels, viz., the alarm-trumpets, in his hand.
Commenting on Numbers 31:3-6