'Available' in the Bible

Here are the names of the descendants of Levi who made themselves available to God: Amasai's son Mahath and Azariah's son Joel from the descendants of Kohath; Abdi's son Kish and Jehallelel's son Azariah from the descendants of Merari; Zimmah's son Joah and Joah's son Eden from the descendants of Gershon;