28. This is the service of the families of the sons of the Gershonites in the tent of meeting, and their duties shall be under the direction of Ithamar the son of Aaron the priest.
29. "As for the sons of Merari, you shall number them by their families, by their fathers' households;
30. from thirty years and upward even to fifty years old, you shall number them, everyone who enters the service to do the work of the tent of meeting.