The Levites, whose responsibility the Tabernacle was, now have their own census. The number of men ages 30-50 in each clan and family is to be logged. This is the age, it is assumed, during which the men would actively assumes their roles working in and around the Tabernacle. Numbers 8:24-25 add the note that the work would be started when the men were 25 years old and that retirement was age 50. There are a few possible reasons why, although 25 was the age at which work was to start, 30 was the age at which they were counted: the first five years could have been a sort of apprenticeship; or the late twenties were not considered reliable years for service (possible time off for marriage, etc.); or for an unknown reason. The next interesting and important note is that although the Kohathites were responsible for moving the items -- doing the carrying -- of the items in the Tabernacle, including those in the Holy of Holies, they were not allowed to see the holy things or to touch them. Thus, it would be Aaron and his sons who would cover these items and put the carrying poles through them. The Kohathites would support the weight of the items by carrying the poles upon which the holy things were suspended. There is an interesting admonition from the Lord in verses 17-20. The Lord gives responsibility for the Kohathite clans to Moses and Aaron, to see they are not cut off from their people and that they do not treat the holy things in such a manner as to cause their own deaths. In other words, Aaron and Moses are to look after the work of the Kohathites in order to protect them, as they are responsible for are protecting and carrying the Tabernacle items. Aaron's two remaining sons were given specific responsibilities. Eleazar was put in charge of the oil for th elight, the incense, the grain offerings, and the anointing oil, or, as verse 16b states, "He is to be in charge of the entire tabernacle and everything in it, including its holy furnishings and articles." Ithamar, Aaron's other son, was put in charge of the two other Levite clans, the Gershonites and the Merarites, and their responsibilities concerning the Tabernacle. All along, from the inception of the Tabernacle in Exodus, the directions from the Lord about it have been detailed and explicit. God does not stand afar off. He is the God who is here. He is the God who cares and is involved.