Dan is in the northern most part of Palestine and would have been the first city to be invaded from the north. Mount Ephraim is the mountainous region lying directly to the north of Jerusalem, closer than Dan. So, in his vision of the future invasion, Jeremiah sees a messenger from the north proclaiming trouble as the enemy sweeps down towards Jerusalem. Jeremiah is giving his listeners a sense of urgency about what is coming.1
15 Car une voix qui part de Dan annonce la calamité, Elle la publie depuis la montagne d'Ephraïm.