Jeremiah 50:4

At the time of Babylon’s destruction, the Israelites would leave her-both Israelites and Judahites. They would go out, weeping as they left, and seeking Yahweh their God. This weeping probably anticipates Israel’s national repentance at the second coming of Christ (cf. Zechariah 12:10-14). Judah and Israel did not unite as one nation after the Persians took over, and most of the exiles did not return to the Promised Land.

"The phrase, In those days (4), is nearly always a pointer to the messianic age to come." [Note: Kidner, p. 149.]