'Required' in the Bible

"{Take them}, and they will be [used] to do the work of the tent of the assembly; and you will give them to the Levites, each {according to his required service}."

Two utility carts and four cattle he gave to the descendants of Gershon {according to their required service};

and four utility carts and eight cattle he gave to the descendants of Merari {according to their required service}, {under the authority of} Ithamar son of Aaron the priest.