C. F. Keil and Franz Delitzsch on Numbers 4:16

Num 4:16

The oversight of the oil for the candlestick (Exo 27:20), the incense (Exo 30:34), the continual meat-offering (Exo 29:40), and the anointing oil (Exo 30:23), belonged to Eleazar as the head of all the Levites (Num 3:32). He had also the oversight of the dwelling and all the holy things and furniture belonging to it; and, as a comparison of Num 4:28 and Num 4:33 clearly shows, of the services of the Kohathites also.