Matthew Poole and continuators on Jeremiah 4:16

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.

These are either the Nations in Iudea, or these words are a Proclamation, summoning in the Nations by the Chaldaeans, as it were in pursuance of a Commission from God, to bring great Armies together against Ierusalem, or they are the Prophets turning away from Iudah, as despairing of doing any good upon them, and calling for the Nations to execute Gods sentence.

Let her be acquainted with what is coming upon her, let her have publick notice before hand, that she may be warned.

Military watchers, i. e. the Chaldaean Souldiers, that shall so carefully and watchfully encompass Ierusalem, that none shall escape; possibly a Metaphor from Hunters, that in hunting their Prey, lay wait at every passage, that the game may not escape, see 2 Kings 25.4, 5. Or possibly, there may be an allusion to Nebuchadnezzar's name, the Heb. word for watchers being Notserim, which comes from natsar, the end of his name, as if they were termed Nebuchadnezzarians, as the keepers, or guards of his person; as they were called Caesareans from Caesar.

They are now at hand, you may as it were see them.

From Chaldaea.

They will proclaim war against them, or a shout, either encouraging Souldiers to the battle, or triumphing after the victory, or the outcries, that they will make such, as the Turks now make in their onsets, chap. 2.15.