Albert Barnes Commentary Jeremiah 1:15

"For, lo, I will call all the families of the kingdoms of the north, saith Jehovah; and they shall come, and they shall set every one his throne at the entrance of the gates of Jerusalem, and against all the walls thereof round about, and against all the cities of Judah." — Jeremiah 1:15 (ASV)

I will call – I am calling. The judgment has begun. God is summoning His hosts to the war.

Families – The various races by which the provinces of the Babylonian empire were populated.

They shall set every one his throne – The chiefs of these various races come as God’s ministers to hold solemn court, and give sentence in His name . They therefore set each one his throne in the usual place for administering justice, namely, the entrance of the gates, where a large open space was always left in cities for the purpose.

Viewed in one light, war is the boiling cauldron of human passion, upset by chance, and bringing only ruin in its course. In the other, it is God sitting in judgment, with the kings of the earth as His assessors, solemnly pronouncing sentence upon the guilty.

Against all the walls ... – Sentence judicially pronounced, the nations come to execute judgment by mounting as enemies upon her walls and storming her cities.