And all the firstborn males by the number of names, from a month old and upward, of those that were numbered of them, were twenty and two thousand two hundred and threescore and thirteen.
Here is the exchange made of the Levites for the first-born. 1. The first-born were numbered from a month old, Num 3:42, Num 3:43. Those certainly were not reckoned who, though first-born, had become heads of families themselves, but those only that were under age; and the learned bishop Patrick is decidedly of opinion that none were numbered but those only that were born since...
Commenting on Numbers 3:40-51
And the Lord spake unto Moses,.... After the number was taken, and gave him directions what to do upon it: saying; as follows.
Num 3:40-48 After this, Moses numbered the first-born of the children of Israel, to exchange them for the Levites according to the command of God, which is repeated in Num 3:41 and Num 3:44-45 from Num 3:11-13, and to adopt the latter in their stead for the service at the sanctuary (on Num 3:41 and Num 3:45, cf. Num 3:11-13).
Commenting on Numbers 3:40-48