Albert Barnes Commentary Jeremiah 4:16

"make ye mention to the nations; behold, publish against Jerusalem, [that] watchers come from a far country, and give out their voice against the cities of Judah." — Jeremiah 4:16 (ASV)

Proclaim to the pagan, Behold! Cry aloud concerning Jerusalem, that watchers are on their way from a far country: and will give out their voice against the cities of Judah. The pagan are summoned to witness the chastisement of Jerusalem, so that they may take warning by it. By “watchers” are meant besiegers, who will surround the city with a line of sentinels.