2CH 35:15

15 And the meshorarim [(singers)], the Bnei Asaph, were in their place, according to the mitzvat Dovid, and Asaph, and Heman, and Yedutun, Chozeh HaMelech; and the sho'arim [(gatekeepers)] were at every sha'ar; neither did they need to depart from their Avodah, for their achim the Levi'im prepared for them.