2 Chronicles 5:11-14

When the priests came out of the Holy Place (for all the priests who were present had sanctified themselves [separating themselves from everything unclean], without regard to their assigned divisions), and all of the Levitical singers, Asaph, Heman, and Jeduthun, with their sons and relatives, clothed in fine linen, with cymbals, harps, and lyres were standing at the east end of the altar, and with them a hundred and twenty priests blowing trumpets in unison when the trumpeters and singers were to make themselves heard with one voice praising and thanking the LORD, and when they raised their voices accompanied by the trumpets and cymbals and [other] instruments of music, and when they praised the LORD, saying, “For He is good, for His mercy and lovingkindness endure forever,” then the house of the LORD was filled with a cloud, so that the priests could not remain standing to minister because of the cloud; for the glory and brilliance of the LORD filled the house of God.