Albert Barnes Commentary Nehemiah 12:27

"And at the dedication of the wall of Jerusalem they sought the Levites out of all their places, to bring them to Jerusalem, to keep the dedication with gladness, both with thanksgivings, and with singing, with cymbals, psalteries, and with harps." — Nehemiah 12:27 (ASV)

The dedication of the wall - The ceremony had been deferred for nearly 12 years (Nehemiah 13:6). Perhaps Nehemiah required express permission from the Persian king before he could venture on a solemnity which might have been liable to misrepresentation.

Out of all their places - That is, out of the various cities of Judah and Benjamin in which they lived (Nehemiah 11:36).