Joshua 21:10

Which the children of Aaron, [being] of the families of the
Kohathites
Who descending from Kohath, in the line of Aaron, were priests:

[who were] of the children of Levi, had;
they were Levites, as descending from Levi, but were priests also, as being of the stock of Aaron, and the cities hereafter mentioned in the said tribe fell to their portion:

for theirs was the first lot;
for being of the line of Aaron, and priests, they had the honour and privilege to have the first lot drawn for them, and out of the tribe for which the first lot was also drawn, the tribe of Judah; here they had their cities allotted them, for a reason before given.