15 The musicians, the descendants of Asaph, were in the places prescribed by David, Asaph, Heman and Jeduthun the king’s seer. The gatekeepers at each gate did not need to leave their posts, because their fellow Levites made the preparations for them.

Read 2 Chronicles 35:15 Using Other Translations

And the singers the sons of Asaph were in their place, according to the commandment of David, and Asaph, and Heman, and Jeduthun the king's seer; and the porters waited at every gate; they might not depart from their service; for their brethren the Levites prepared for them.
The singers, the sons of Asaph, were in their place according to the command of David, and Asaph, and Heman, and Jeduthun the king's seer; and the gatekeepers were at each gate. They did not need to depart from their service, for their brothers the Levites prepared for them.
The musicians, descendants of Asaph, were in their assigned places, following the commands that had been given by David, Asaph, Heman, and Jeduthun, the king’s seer. The gatekeepers guarded the gates and did not need to leave their posts of duty, for their Passover offerings were prepared for them by their fellow Levites.