Jeremiah 41:18
Because of the Chaldeans: for they were afraid of them, because Ishmael the son of Nethaniah had slain Gedaliah the son of Ahikam, whom the king of Babylon made governor in the land. Because of the Chaldeans: for they were afraid of them, because Ishmael the son of Nethaniah had slain Gedaliah the son of Ahikam, whom the king of Babylon made governor in the land.
Jeremiah 41:18 stands in chapters 32 to 45, which give the history of the two years before the fall of Jerusalem, in the portion of the book uttered during the rule of Gedaliah. It belongs to the account of the remnant of Jews left in the land and gathered in Judah after Zedekiah's captivity, after Babylon had carried the nation away. It belongs also to the account of Jeremiah's personal experiences and his going into Egypt with them before their later flight to Egypt.
The verse means the people were afraid of the Chaldeans because Ishmael the son of Nethaniah had slain Gedaliah the son of Ahikam, whom the king of Babylon had made governor in the land. That king was Nebuchadnezzar, who had left Gedaliah as viceroy in the land of Judah after the destruction of Jerusalem. In the sequence of events, the king of Ammon dispersed the Jewish remnant gathered in Judah. Chapter 41 recounts Gedaliah's assassination at Mizpah and the scattering of the remnant left in the land by the king of Babylon.
Because they feared the Chaldeans after the killing, the people went to seek refuge in Egypt. They had been advised to remain in the land under Babylonian rule, where they would have protection if they heeded Jeremiah, but they chose to go to Egypt. Gedaliah's assassination is the reason for the Jews' fast in the seventh month. It is commemorated as the Fast of Gedaliah on Tisri 3, one of the four fasts commemorating events connected with the fall of Jerusalem, which like the other three begins at daybreak.