John Gill Commentary Jeremiah 30:4

"And these are the words that Jehovah spake concerning Israel and concerning Judah." — Jeremiah 30:4 (ASV)

And these are the words that the Lord spoke concerning Israel ,
and concerning Judah .
] Which follow in this chapter and the next; first concerning Israel, the ten tribes; and then concerning the two tribes of Judah and Benjamin, even concerning all Israel; whereas, if this prophecy only respects the return from the captivity in Babylon, there is very little in it which concerns the ten tribes, or but a very few of them. The words may be rendered, "unto Israel, and unto Judah"; as being the persons to whom they were directed, as well as were the subjects of them.