Bible Verses About The Levites: Divided them into four classed

Of these twenty-four thousand were chosen, and distributed unto the ministry of the house of the Lord: and six thousand were the overseers and judges.

Moreover four thousand were porters: and as many singers singing to the Lord with the instruments, which he had made to sing with.

And David distributed them into courses by the families of the sons of Levi, to wit, of Gerson, and of Caath, and of Merari.