2 Kings 14:25 (ESV)

25 He restored the border of Israel from Lebo-hamath as far as the Sea of the Arabah, according to the word of the LORD, the God of Israel, which he spoke by his servant Jonah the son of Amittai, the prophet, who was from Gath-hepher.

Jeroboam expands the area of Israel considerably (see also 2 Kings 14:28). The king of Judah is able to do the same (see 2 Chronicles 26:1–23); and so, both kingdoms together had the same size again as in the time of David. This was prophesied by Jonah—the same prophet as in the Bible book with that name.