A small number of Levites had returned a couple of generations ago with Sheshbazzar (Ezra 2:36). Ezra had drafted more to return with him to the Promised Land (Ezra 8:15–20). The task of these Levites, of course, was to teach the people the way of the Lord and do whatever tasks were their prerogative in the (reconstructed) temple. Nehemiah now records that a number of these Levites found opportunity away from their regular work to help reconstruct the wall. Nehemiah 3:17–21 supplies the names of these teachers.
17 After him the Levites repaired: Rehum the son of Bani. Next to him Hashabiah, ruler of half the district of Keilah, repaired for his district.