‘We have heard news of them,
our hands fall helpless;
anguish has taken hold of us,
pain as of a woman in labor.
Do not go out into the field,
or walk on the road;
for the enemy has a sword,
terror is on every side.’
O my poor people, put on sackcloth,
and roll in ashes;
make mourning as for an only child,
most bitter lamentation:
for suddenly the destroyer will come upon us.
The prophecies of Jeremiah very often include warnings about invaders coming from the north. In general, they are seen as consequences of the choices of the Hebrew people and—in particular—of their leaders.
Here the prophet warns his people that things are about to change dramatically. He is not advising that they change their actions—it seems that it's already too late for that. The choices have been made, and the consequences of those choices are at hand. Jeremiah warns the people to be prepared.