2 Chronicles 5:11-12

11Now all the priests who were present had consecrated themselves regardless of their divisions. And when the priests came out of the Holy Place, 12all the Levitical singers—Asaph, Heman, Jeduthun, and their sons and relatives—stood on the east side of the altar, dressed in fine linen and playing cymbals, harps, and lyres, accompanied by 120 priests sounding trumpets.