The scribe and prophet Ezra was born in Babylon, but under the Persians c 480 BC after the exile was over. He moved to Jerusalem, where the Temple had been rebuilt, and reintroduced the Torah there.
In their attitude towards gentiles, Jews today are still the prisoners of the masterful Babylonian Jewish reformer Ezra. His objective was to make the Jews obey the Torah; and, as a necessary means to this end, he took drastic steps to segregate them from their gentile neighbours. “The general result of his policy was to draw a sharp line of division between Jew and gentile, and to make for the Jewish community a sort of enclosure in the midst of the gentile world.” This was an inevitable effect of enforcing the observance of the Torah as Ezra understood it. But the observance of the Torah as understood by Ezra and by his successors the Pharisees is not an inevitable accompaniment of the religion of Deutero-Isaiah [the exilic “second Isaiah”]. Ezra raised an issue. He did not settle it. And the debate that he started has been continuing in Jewish hearts and minds ever since.
The quotation is from R Travers Herford, Judaism in the New Testament Period, Lindsey Press, 1928. The passage also refers to his The Pharisees, Allen & Unwin, 1924.
A Study of History, Vol XII: Reconsiderations, OUP, 1961