Albert Barnes Commentary 2 Chronicles 9:28

"And they brought horses for Solomon out of Egypt, and out of all lands." — 2 Chronicles 9:28 (ASV)

And out of all lands - This is an addition to the words in Kings. The principal countries would no doubt be Arabia and Armenia—the former always famous for its excellent breed, the latter mentioned in Ezekiel 27:14 as trading with horses in the markets of Tyre.