King over the Kings
God promised to discipline His covenant people for their rebellion and idolatry through various means, of which God reserved foreign invasion as a severe consequence. Although the Northern and the Southern Kingdoms were divided, God kept His promise to discipline both regions through the surrounding nations. During the time of Isaiah, Assyria was such a nation used by God. But why would a holy God use an unholy nation for such a sacred purpose? Only the King of all Kings is all-wise and powerful to carry out such a righteous plan.