4. Command them. Jeremiah was commissioned to tell the representatives of the kings named in 3 that their endeavors would be futile; that in the providence of God, Babylon was to be the irresistible conqueror of nations, the divine instrument to punish them for their iniquities.
The Lord of hosts. See on 7:3. This title applied to “the God of Israel” was specially used to impress upon the nations that knew not the Lord, that the true God, the God of the “hosts” of heaven, was more than a match for the armies of earth (see on Joshua 5:14; Ps. 24:10).