Joshua 21:9,10

‘ And they gave out of the tribe of the children of Judah, and out of the tribe of the children of Simeon, these cities which are here mentioned by name (literally ‘which one calls by name'), and these were for the children of Aaron, of the families of the Kohathites, who were of the children of Levi, for theirs was the first lot.'

The first lot was for the family of Aaron as priests of the land. The names of the cities allocated to them in Judah and Simeon are to be listed. Their descent is clearly outlined.