To redeem the 273 firstborn Israelites who outnumber the Levites,
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
Thou shall even take five shekels apiece the poll,.... Or head; every firstborn, or his parent for him, was bound to pay five shekels, which were about eleven or twelve shillings of our money, and which was afterwards settled as the price of such a redemption, Num 18:16, after the shekel of the sanctuary shall thou take them; being full weight according to the standard...
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