It is unclear what happened to these faithful Jews and Israelites. It is known that those who returned from Babylonian captivity with Zerubbabel to rebuild Jerusalem were from Judah, Benjamin and Levi (Er 1:5). Later it is recorded that more Levites came with Ezra (Er 7:7). Perhaps some of these faithful Jews and Israelites were still present at this time as those coming with Zerubbabel received no opposition when they first arrived in Jerusalem (Er 2:68). These faithful Israelites and Jews left in the land likely became incorporated into those classified as Jews from that time forth.
There were some nationals that had been left in the land of Israel and Judah that over time intermarried with those brought in from other areas or that lived in the area. These were excluded from helping with the reconstruction and from their temple worship (Er 4:2-3). The main reason was their alliances had led them away from the worship of God. Although they had a form of worship (Er 4:2), God was not the only god they worshipped (2Ki 17:32-34) and, by God’s standards, were not truly worshippers of God Himself (2Ki 17:35-41). These were therefore considered Gentiles even though they had Israeli or Jewish roots.
There were other pockets of Jews or Israelites that also have to be considered: those of the kingdom of Judah that remained in Babylonian territories rather than returning to Jerusalem, those of the kingdom of Israel that were spread to many areas just before and during their Assyrian captivity, those Judeans who settled in Egypt after the assassination of Gedaliah (Jr 43:4-7), and an Israelite community in the land of Ammon during the time of the Restoration. It seems when Tobiah was thrown out of the temple in Jerusalem by Nehemiah (Ne 13:4-9), he went back to Ammon and built a similar temple.
Prior to the Northern Kingdom of Israel being taken into captivity, the threat of captivity by Tiglath-pileser of Assyria and the drought that had occurred earlier during the time of Elijah caused a mass exodus of Israelis to other areas prior to the nation’s final captivity. Many fled to Kirjath-Hadeschath, which later became known as Carthage (in present-day Tunis in North Africa), and others fled over land to Armenia and land north of the Black Sea. This created several pockets of Israelis throughout the known world. Those that migrated into the areas around Armenia later became the leaders of the kingdom of Parthia which was a nation as powerful as, and a rival of, Rome. The national Jews in the first century knew of these Jews and Israelis that were not part of national Judea, as noted by Josephus.
It is likely that none of these groups, except those that may have gone with Tobiah, would have been considered “Gentile” by these Jews that returned to Jerusalem. Even during the time of Christ, these other Jewish settlements were well known to the national Jews. Actually, at that time, Jews were all over the known world. However, those in the Roman Empire were mainly Jewish while those in the Parthian Empire were both of Jewish and Israeli descent. Even at that time, these would likely not be considered Gentile. It would not be until the defeat of the Parthian Empire and the exodus of these Israeli descendants into Europe that the term Gentile would be applied to anyone outside those of national Judea that did not maintain their national heritage. Those that blended in with these other nations into which they lived seem to slowly lose their identity with those of national Judea and over time had no real connection with their original national heritage. Therefore, as the classification for being Jewish decreased over time, the classification for being Gentile increased over time.
Gentiles – World View