The Assyrian government encouraged its residents to move to Israel and to settle there after the fall of the Northern Kingdom in722 B.C. This was official government policy during the reigns of the Assyrian kings Esarhaddon (680-669 B.C.; 2 Kings 17:24) and Ashurbanipal (668-ca630 B.C.; Ezra 4:10). These immigrant people worshipped pagan idols ( 2 Kings 17:30-31), but also started worshipping Yahweh, whom they regarded as the god of the land in which they now lived ( 2 Kings 17:32-33). Eventually they intermarried with the Jews who had remained in the land. Their descendants became the Samaritans, a mixed breed racially and religiously. The exiles who returned from Babylon and their descendants despised them (cf. John 4:9). It was these people of the land who approached Zerubbabel and offered to help the Jews rebuild their temple ( Ezra 4:2). [source][source][source]
"But "people of the land" is a vague term being attached to different groups during different phases of the historical period and having no inner continuity to the term itself. Chronologically, it cannot refer to Samaritan opposition, since the Samaritan sect is a much later emergence." [1][source]
Zerubbabel refused their offer because, even though they worshipped Yahweh, they did not worship Him exclusively, as the Mosaic Law specified ( Exodus 20:3). Zerubbabel realized that if their commitment to God did not include a commitment to obey His revealed will, the Jewish remnant could only anticipate endless disagreement, conflict, and frustration with them. [source][source][source]
"This attitude of exclusiveness displayed by the Jews ... is troublesome to our modern society, where perhaps the highest virtue is the willingness to accept and cooperate with persons whose beliefs and practices differ from one"s own. If we are tempted to think that Zerubbabel and the other leaders were sinfully separatistic or mistaken in their evaluation of those who offered their assistance, we must observe that these outsiders are identified as "enemies." Their motives were clearly subversive." [2][source]
"The leaders in the province of Samaria may well have seen the emergence of a new, aggressive presence in Judah, and one which enjoyed the favor of the imperial government, as threatening.... An offer to share the labor, and presumably also the expense, of rebuilding the sanctuary would have been taken to entail, and would in fact have entailed, a share in controlling the temple itself with all that implied." [3][source]
The fact that these neighbors had no sincere interest in helping the Jews became obvious very quickly ( Ezra 4:4-5). Their persistent opposition continued into the reign of Darius I (Hystaspes) of Persia (521-486 B.C.). [source][source][source]
"The Persian officials were bribed to frustrate the plans of the returnees. Bribery as a practice was well known in Persian times." [4][source]
Persian Kings of the Restoration PeriodKingsReignsScriptureCyrus II (the Great)559-530 Ezra 1:1; Ezra 4:5Cambyses530-522Smerdis522Darius I521-486 Ezra 5-6; Haggai; ZechariahXerxes (Ahasuerus)486-464 Ezra 4:6; EstherArtaxerxes I (Artashasta)464-424 Ezra 4:7-23; chs7-10; Nehemiah; MalachiDarius II423-404 Nehemiah 12:22[source]
Opposition during Ahasuerus" reign4:6[source]
"When he [5] discussed the problems of the building of the temple in Ezra 4:1-5, it reminded him of later similar troubles with the rebuilding of the wall of Jerusalem, and Song of Solomon 4:6-16 has been inserted, almost parenthetically, before the argument of the building of the temple has again been taken up in Ezra 4:24 ff. (already noted by C. F. Keil in the last [4]3 century)." [7][source]
This king of Persia, whose Greek name was Xerxes, was the man Esther married. He ruled from486 to464 B.C. Since the restoration Jews completed the temple in515 B.C. ( Ezra 6:15), this verse shows that the neighbors of the returned exiles continued to oppose them long after they had finished rebuilding the temple. [source][source][source]
"Without this foretaste of history to reveal the full seriousness of the opposition, we would not properly appreciate the achievements recorded in the next two chapters (5,6) nor the dangers hidden in the mixed marriages which Ezra would set himself to stamp out (chaps7-10)." [8][source]