Complete Commentary on the Whole Bible, by Matthew Henry, at sacred-texts.com
(Num 4:1-3) The Levites' service.
(v. 4-20) The duties of the Kohathites.
(Num 4:21-33) The duties of the Gershonites and Merarites.
(v. 34-49) The numbers of the serviceable Levites.
The middle-aged men of the tribe of Levi, all from thirty years old to fifty, were to be employed in the service of the tabernacle. The service of God requires the best of our strength, and the prime portion of our time, which cannot be better spent than to the honour of Him who is the First and Best. And the service of God should be done when we are most lively and active. Those do not consider this who put off repentance to old age, and so leave the best work to be done in the worst time.
The Kohathites were to carry the holy things of the tabernacle. All the holy things were to be covered; not only for security and respect, but to keep them from being seen. This not only marked the reverence due to holy things, but the mystery of the things signified by those types, and the darkness of the dispensation. But now, through Christ, the case is altered, and we are encouraged to come boldly to the throne of grace.
We have here the charge of the other two families of the Levites, which, though not so honourable as the first, yet was necessary, and to be done regularly. All the things were delivered them by name. It intimates the care God takes of his church and every member of it. The death of the saints is represented as the taking down of the tabernacle, Co2 5:1, and the putting it off, Pe2 1:14. All shall be raised up in the great day, when these vile bodies shall be made like the glorious body of Jesus Christ, and so shall be for ever with the Lord.
God so ordered it, that though the Merarites were the fewest in number, yet they should have most able men among them; for whatever service God calls men to, he will furnish them for it, give strength in proportion to the work, and grace sufficient. The least of the tribes had many more able men than the Levites: those who engage in the service of this world, are many more than those devoted to the service of God. May our souls be wholly devoted to his service.