Rezon was Israel’s enemy throughout the days of Solomon, adding to the trouble caused by Hadad. So Rezon ruled over Aram with hostility toward Israel.
Jewish Publication Society of America Version (JPS1917) - 1 Kings 11:25 >And he was an adversary to Israel all the days of Solomon, beside the mischief that Hadad did; and he abhorred Israel, and reigned over Aram.