Albert Barnes Commentary 2 Chronicles 9:23

"And all the kings of the earth sought the presence of Solomon, to hear his wisdom, which God had put in his heart." — 2 Chronicles 9:23 (ASV)

All the kings of the earth - Rather, “all the kings of the land:” all the monarchs, that is, whose dominions were included in Solomon’s empire (see 1 Kings 4:21).