What does 2 Kings 9:20 mean?

Now the watchman was standing on the tower in Jezreel, and he spied the company of Jehu as he came, and said, “I see a company.” Joram said, “Take a horseman, and send to meet them, and let him say, ‘Is it peace?’”

So one went on horseback to meet him, and said, “Thus says the king, ‘Is it peace?’” Jehu said, “What do you have to do with peace? Fall in behind me!” The watchman said, “The messenger came to them, but he isn’t coming back.”

Then he sent out a second on horseback, who came to them, and said, “Thus says the king, ‘Is it peace?’” Jehu answered, “What do you have to do with peace? Fall in behind me!”

Joram said, “Get ready!” They got his chariot ready. Then Joram king of Israel and Ahaziah king of Judah went out, each in his chariot, and they went out to meet Jehu, and found him on Naboth the Jezreelite’s land.

When Joram saw Jehu, he said, “Is it peace, Jehu?” He answered, “What peace, so long as the prostitution of your mother Jezebel and her witchcraft abound?”

Joram turned his hands, and fled, and said to Ahaziah, “This is treason, Ahaziah!”