Thematic Bible: Conducting the sacred music

And the Levitical singers, all of them of Asaph, of Heman, of Jeduthun, with their sons and their brothers, being clothed in white linen, having cymbals and with harps and lyres, stood at the east end of the altar, and with them a hundred and twenty priests sounding with trumpets, and they were as one to the trumpeters and to the singers, to make one sound to be heard in praising and thanking Jehovah; and as they lifted up their voice with the trumpets and cymbals and instruments of music, and praised Jehovah, saying, For He is good, for His mercy endures forever, the house was filled with a cloud, the house of Jehovah,

And four thousand were gatekeepers, and four thousand praised Jehovah with the instruments which David made for praising. And David divided them into courses among the sons of Levi, Gershon, Kohath and Merari. Of the men of Gershon were Laadan and Shimei. read more.
The sons of Laadan: Jehiel the chief, and Zetham, and Joel, three. The sons of Shimei: Shelomith, and Haziel, and Haran, three. These were the chief of the fathers of Laadan. And the sons of Shimei: Jahath, Zina, and Jeush, and Beriah. These four were the sons of Shimei. And Jahath was the chief, and Zizah the second. But Jeush and Beriah did not have many sons. Therefore they were in one roster, according to their father's house. The sons of Kohath: Amram, Izhar, Hebron, and Uzziel, four. The sons of Amram: Aaron and Moses. And Aaron was separated so that he should sanctify the most holy things, he and his sons forever, to burn incense before Jehovah, to minister to Him, and to bless in His name forever. And as to Moses the man of God, his sons were named of the tribe of Levi. The sons of Moses: Gershom and Eliezer. Of the sons of Gershom, Shebuel was the chief. And the sons of Eliezer: Rehabiah the chief. And Eliezer had no other sons, but the sons of Rehabiah were very many. Of the sons of Izhar, Shelomith was the chief; of the sons of Hebron, Jeriah the first, Amariah the second, Jahaziel the third, and Jekameam the fourth. Of the sons of Uzziel, Michah the first, and Jesiah the second. The sons of Merari: Mahli and Mushi. The sons of Mahli: Eleazar and Kish. And Eleazar died, and had no sons, but had daughters. And their brothers, the sons of Kish, took them. The sons of Mushi: Mahli, and Eder, and Jeremoth, three. These were the sons of Levi after the house of their fathers, the chief of the fathers, as they were counted by number of names by their heads, the ones who did the work for the service of the house of Jehovah, from the age of twenty years and upward. For David said, Jehovah, the God of Israel has given rest to His people so that they may dwell in Jerusalem forever, and also to the Levites, so that they shall no more carry the tabernacle, nor any of its vessels for its service. For by the last words of David the Levites were numbered from twenty years old and above, because their office was to wait on the sons of Aaron for the service of the house of Jehovah, in the courts and in the chambers, and in the purifying of all holy things, and the work of the service of the house of God both for the showbread, and for the fine flour for food offering, and for the unleavened cakes, and for the pan, and for that which is fried, and for all kinds of measure and size, and to stand every morning to thank and praise Jehovah, and likewise at evening.