The cities of the priests - i. e. the Levitical cities (compare marginal reference). Of these, some had gone to decay, while others, as Libnah and Beth-shemesh 2 Chronicles 21:10; 2 Chronicles 28:18, had been lost, so that the original number, thirteen, was now, apparently, reduced to six.
In their set office - Rather, as in marg. These six Levites were stationed at the Levitical cities, with the trust following committed to them.