Ezra 2:13

The children of Adonikam, six hundred sixty and six.

The verse records that 666 descendants of Adonikam returned to Jerusalem in response to Cyrus's decree. It is part of the Ezra 1-2 list, within the Ezra 1-6 history, of those who returned to Jerusalem from captivity to their own land after Cyrus's proclamation and decree to rebuild the temple, marking the beginning and rebuilding of the temple. The return was led by Zerubbabel in the first year of Cyrus. The people who thus returned numbered 42,360.

That total is also given as nearly fifty thousand. Their departure marked the end of the captivity because all were free to go, though many remained behind. That history belongs to the same time as Haggai, when the city was in a dilapidated condition and the temple building was languishing.

The verse does not belong to B.C. 457. B.C. 457 marks the different event of the going forth of the commandment to restore and to build Jerusalem predicted in Daniel 9:25. That commandment was the commandment of God carried out through Cyrus, Darius, and Artaxerxes and complete only when the last king acted in the seventh year of Artaxerxes.