2 Chronicles 5:11-12

11Then the priests left the Holy Place. All the priests who were present had purified themselves, whether or not they were on duty that day.

12And the Levites who were musicians—Asaph, Heman, Jeduthun, and all their sons and brothers—were dressed in fine linen robes and stood at the east side of the altar playing cymbals, lyres, and harps. They were joined by 120 priests who were playing trumpets.