4:4 people of the land. These “people of the land” thus demonstrated their insincerity in offering to help build the temple. They claimed to worship the true God of creation as Israel did (Ezra 4:2) but actually they had mixed this with the worship of the pagan gods of Israel’s ancient adversaries (II Kings 17:33). It was vital that true Biblical theism not be corrupted with pagan pantheism.
4:5 frustrate their purpose. Ezra 4:6-24 seems to constitute a general summary by Ezra of the opposition received against the rebuilding of the temple during the reigns of four different emperors of Persia: first Cyrus (approximately 550–530 B.C.), later also Ahasuerus (or Xerxes), Artaxerxes I and Darius Hystaspes. The precise chronology and identification of these kings are uncertain and controversial, even among conservative scholars, but the general history and message are clear.
4:6 Ahasuerus. Ahasuerus is considered the Hebrew equivalent of Xerxes, probably the Xerxes whose fleet was defeated by the Greeks in 480 B.C. If so, he was probably also the Ahasuerus who married Queen Esther (Esther 1:1). Others identify him as Cambyses, the son of Cyrus.
4:7 Syrian tongue. The “Syrian tongue” is the Aramaic language. Although the Old Testament was written in Hebrew, a few portions are written in Aramaic. One such section is Ezra 4:8-6:18.
4:8 Artaxerxes. This is believed to be either the short-lived King Smerdis, who succeeded Cambyses, or the emperor who granted Ezra the decree he requested to go to Jerusalem (Ezra 7:13), and later to Nehemiah as well (Nehemiah 2:1-8). He was, thus, possibly the stepson of Queen Esther.
4:10 Asnapper. Asnapper is believed to be the same as Ashurbanipal, the last truly great king of the Assyrian empire.
4:10 the river. The “river” here means the Euphrates.