This command was carried out by Moses and Aaron. They took for this purpose the twelve heads of tribes who are pointed out (see at Leviticus 24:11) by name, and had the whole congregation gathered together by them and enrolled in genealogical tables. התילּד, to announce themselves as born, i.e., to have themselves entered in genealogical registers (books of generations). This entry is called a פּקד, mustering, in Numbers 1:19, etc. In vv. 20-43 the number is given of those who were mustered of all the different tribes, and in Numbers 1:44-47 the total of the whole nation, with the exception of the tribe of Levi. "Their generations" (Numbers 1:20, Numbers 1:22, Numbers 1:24, etc.), i.e., those who were begotten by them, so that "the sons of Reuben, Simeon," etc., are mentioned as the fathers from whom the mishpachoth and fathers' houses had sprung. The ל before שׁמעון בּני in Numbers 1:22, and the following names (in Numbers 1:24, Numbers 1:26, etc.), signifies "with regard to" (as in Isaiah 32:1; Psalm 17:4, etc.).

Numbers 1:44 Parallel Commentaries

Numbers 1:2-16 Take you the sum of all the congregation of the children of Israel, after their families, by the house of their fathers...

Numbers 26:64 But among these there was not a man of them whom Moses and Aaron the priest numbered...