3:40-51 The number of the first-born, and that of the Levites, came near to each other. Known unto God are all his works beforehand; there is an exact proportion between them, and so it will appear, when they are compared together. The small number of first-born, over and above the number of the Levites, were to be redeemed, and the redemption-money given to Aaron. The church is called the church of the first-born, which is redeemed, not as they were, with silver and gold; but, being devoted by sin to the justice of God, is ransomed with the precious blood of the Son of God. All men are the Lord's by creation, and all true christians are his by redemption. Each should know his own post and duty; nor can any service required by such a Master be rightly accounted mean or hard.

41. the cattle of the Levites—These, which they kept to graze on the glebes and meadows in the suburbs of their cities, to supply their families with dairy produce and animal food, were also taken as an equivalent for all the firstlings of the cattle which the Israelites at that time possessed. In consequence of this exchange the firstlings were not brought then, as afterwards, to the altar and the priests.