Albert Barnes Commentary Ezra 7:24

"Also we certify you, that touching any of the priests and Levites, the singers, porters, Nethinim, or servants of this house of God, it shall not be lawful to impose tribute, custom, or toll, upon them." — Ezra 7:24 (ASV)

The decree of Artaxerxes was more favorable to the Jews than those of all previous Persian monarchs. We hear of a similar exemption of ecclesiastics from tribute, only to a less extent, under the Seleucidae.

Ministers - The rare word here used, which in Daniel has the sense of “worshippers,” appears to designate in this place the lowest class of persons employed in the service of the temple.