'Priests and Levites' in the Bible

By me hath been made a decree that every one who is willing, in my kingdom, of the people of Israel and of its priests and Levites, to go to Jerusalem with thee, doth go;

'And to you we are making known, that upon any of the priests and Levites, singers, gatekeepers, Nethinim, and servants of the house of God, tribute and custom there is no authority to lift up.