“Judah and Benjamin.” The two tribes that made up the nation of “Judah.” After Solomon died, the United Kingdom of Israel, which was 12 tribes was split into “Israel,” which had ten tribes and “Judah,” which was composed of Benjamin and Judah. Israel was carried away captive by the Assyrians (2 Kings 17:1-23). Years later, Judah was deported by the Babylonians but were allowed to return to their homeland by the Persians. Nevertheless, history shows us that the majority of Judeans stayed where they had settled and remained in Mesopotamia.
“exiles who had returned.” The Hebrew is idiomatic: “the sons of the exile,” that is, those who had been taken captive to Babylon by Nebuchadnezzar but had now returned to Judah.