John Gill's Bible Commentary Ver. 1. And the Lord spake unto Moses, and unto Aaron , etc.] After they had taken the number of the Levites, and made an exchange of the firstborn of Israel for them; and now they are ordered to number them a second time, and take out from them such as were fit for service: saying ; as follows.
Matthew Henry Commentary
Verses 1-3 - 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 portio of our time, which cannot be better spent than to the honour of Him wh 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 of repentance to old age, and so leave the best work to be done in the worst time.
Original Hebrew וידבר1696 יהוה3068 אל413 משׁה4872 ואל413 אהרן175 לאמר׃559