Adam Clarke on Jeremiah 34:1

The word which came unto Jeremiah - This discourse was delivered in the tenth year of the reign of Zedekiah. The chapter contains two discourses; one, Jer 34:1-7, which concerns the taking of the city, and Zedekiah's captivity and death; the other, Jer 34:8-22, which is an invective against the inhabitants of Jerusalem for having Hebrew male and female slaves. These, having been manumitted at the instance of the prophet, were afterwards brought back by their old masters, and put in the same thraldom; for which God threatens them with severe judgments.

Nebuchadnezzar - and all his army, and all the kingdoms of the earth of his dominion - That is, his army was composed of soldiers gathered out of Babylon, and out of all his tributary dominions: one hundred and twenty provinces.