1 Chronicles 23:5-7

King James Version

⁵ Moreover four thousand were porters; and four thousand praised the Lord with the instruments which I made, said David, to praise therewith.

⁶ And David divided them into courses among the sons of Levi, namely, Gershon, Kohath, and Merari.

⁷ Of the Gershonites were, Laadan, and Shimei.