What does Ezra 8:18 mean?

I gathered them together to the river that runs to Ahava; and there we encamped three days: and I looked around at the people the priests, and found there were none of the sons of Levi.

Then sent I for Eliezer, for Ariel, for Shemaiah, for Elnathan, for Jarib, for Elnathan, for Nathan, for Zechariah, and for Meshullam, chief men; also for Joiarib and for Elnathan, who were teachers.

I sent them out to Iddo the chief at the place Casiphia; and I told them what they should tell Iddo, and his brothers the temple servants, at the place Casiphia, that they should bring to us ministers for the house of our God.

and Hashabiah, and with him Jeshaiah of the sons of Merari, his brothers and their sons, twenty;

and of the temple servants, whom David and the princes had given for the service of the Levites, two hundred twenty temple servants. All of them were mentioned by name.

Then I proclaimed a fast there, at the river Ahava, that we might humble ourselves before our God, to seek from him a straight way for us, and for our little ones, and for all our possessions.