What does Nehemiah 12:25 mean?

As for the Levites, in the days of Eliashib, Joiada, and Johanan, and Jaddua, there were recorded the heads of fathers’ households; also the priests, in the reign of Darius the Persian.

The sons of Levi, heads of fathers’ households, were written in the book of the chronicles, even until the days of Johanan the son of Eliashib.

The chiefs of the Levites: Hashabiah, Sherebiah, and Jeshua the son of Kadmiel, with their brothers close to them, to praise and give thanks, according to the commandment of David the man of God, watch next to watch.

These were in the days of Joiakim the son of Jeshua, the son of Jozadak, and in the days of Nehemiah the governor, and of Ezra the priest and scribe.

At the dedication of the wall of Jerusalem, they sought the Levites out of all their places, to bring them to Jerusalem, to keep the dedication with gladness, both with giving thanks, and with singing, with cymbals, stringed instruments, and with harps.

The sons of the singers gathered themselves together, both out of the plain around Jerusalem and from the villages of the Netophathites;