Priests in their apparel. The priestly garments which the people had recently provided were designed “for glory and for beauty” according to the Mosaic law.
With trumpets. The blowing of trumpets was a priestly prerogative, while cymbals were the musical instruments played by Levites.
After the ordinance of David. This ordinance is given in 1 Chron. 15:16-24. However, Zerubbabel’s musical service fell short of the “ordinance of David,” since it failed to provide for several instruments that were an essential part of David’s system. Apparently, the musical training of the Levites had been neglected during the Exile.