Of the people of Gad, their generations, by their clans, by their fathers’ houses, according to the number of the names, from twenty years old and upward, all who were able to go to war:
We have here the speedy execution of the orders given for the numbering of the people. It was begun the same day that the orders were given, The first day of the second month; compare Num 1:18 with Num 1:1. Note, When any work is to be done for God it is good to set about it quickly, while the sense of duty is strong and pressing.
Commenting on Numbers 1:17-43
Num 1:17-47 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 Lev 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).
Commenting on Numbers 1:17-47