Numbers 1:4

“And with you there shall be a man of every tribe, etc.] Excepting Levi, of which Moses and Aaron were, to assist in taking the account, and to see that it was an exact and perfect one: everyone head of the house of his fathers; and prince of the tribe he belonged to, as appears from (<040116>Numbers 1:16) and (<040702>Numbers 7:2), where an account is given of the same persons as princes of the tribes that offered at the dedication of the altar, who here assisted in the taking this account; the Targum of Jonathan calls them each a prince, as Prince Elizur, etc.”

“with you there shall be a man of every tribe, &c.--The social condition of the Israelites in the wilderness bore a close resemblance to that of the nomad tribes of the East in the present day. The head of the tribe was a hereditary dignity, vested in the oldest son or some other to whom the right of primogeniture was transferred, and under whom were other inferior heads, also hereditary, among the different branches of the tribe. The Israelites being divided into twelve tribes, there were twelve chiefs appointed to assist in taking the census of the people.”

“A month had passed away since the setting up of the tabernacle Exodus 40:2, Exodus 40:17 : and the Sinaitic legislation was now complete (compare Leviticus 27:34). A census (“sum”) was commanded, to be based not upon any fresh registration of individuals, but upon that which had accompanied the previous collection of the offerings. Compare Exodus 30:11, etc.; Exodus 38:25-28. The offerings had been probably tendered by the people in groups, and if certificates of registration were furnished to such groups, the new census might be easily carried out by means of these documents, and got through Numbers 1:18 in a single day. The present registration enrolled persons “after their families, by…”

“Num 1:16, 2:3-31, 7:10-83, Num 10:14-27, Num 13:2-15, Num 17:3, Num 25:4, Num 25:14, Num 34:18-28; Exo 18:25; Jos 22:14; 1Chr. 27:1-22 Numbers 1:5”

“Moses and Aaron, who were commanded to number, or rather to muster, the people, were to have with them "a man of every tribe, who was head-man of his fathers' houses," i.e., a tribe-prince, viz., to help them to carry out the mustering. Beth aboth ("fathers' houses"), in Num 1:2, is a technical expression for the subdivisions in which the mishpachoth, or families of the tribes, were arranged, and is applied in Num 1:4 according to its original usage, based upon the natural division of the tribes into mishpachoth and families, to the fathers' houses which every tribe possessed in the family of its first-born. In Num 1:5-15, these heads of tribes were mentioned by name, as in Num 2:3., Num…”