Adam Clarke on 2 Kings 14:9

Jehoash - sent to Amaziah - saying - The meaning of this parable is plain. The thistle that was in Lebanon - Amaziah, king of Judah, sent to the cedar that was in Lebanon - Jehoash, king of Israel, saying, Give thy daughter - a part of thy kingdom, to my son to wife - to be united to, and possessed by the kings of Judah. And there passed by a wild beast - Jehoash and his enraged army, and trode down the thistle - utterly discomfited Amaziah and his troops, pillaged the temple, and broke down the walls of Jerusalem: see 2Kgs 14:12-14. Probably Amaziah had required certain cities of Israel to be given up to Judah; if so, this accounts for that part of the parable, Give thy daughter to my son to wife.