Music. 1 Samuel 18:6; Isaiah 30:29. The practice of music was not restricted to any one class of persons. 1 Chronicles 13:8; 1 Chronicles 15:16. The sons of Asaph, Heman, and Jeduthun were set apart by David for the musical service. They were divided, like the priests, into 24 courses, which are enumerated. 1 Chronicles 25:1-31. Of the 38,000 Levites, "four thousand praised the Lord with the instruments." 1 Chronicles 23:5. Each of the courses or classes had 154 musicians and three leaders, and all were under the general direction of Asaph and his brethren. Each course served for a week, but upon the festivals all were required to be present, or four thousand musicians. Heman, with one of his leaders, directed the central choir, Asaph the right, and Jeduthun the left wing. These several choirs answered one another, as is generally supposed, in that kind of alternate singing which is called "antiphonal," or responsive. The priests, in the meantime, performed upon the silver trumpets. 2 Chronicles 5:11-14; Numbers 10:2.