The title Lord God of hosts
emphasizes God’s covenantal relationship with his people and God’s ability to take action to save them. Many nations, including Egypt and Canaan, had shuddered under the wrath of God. Now this wrath was directed against Israel. To the psalmist, the destruction was not primarily the work of the Assyrians. It was firstly God who was avenging himself for the Baal worship of the Ephraimites. Even though they were breakers of the covenant, the psalmist still referred to these tribes as your people.
The sheep may be lost, but they are still sheep. Although under God’s wrath they were still God’s people, it is because they belong to him that his anger is so severe.
4 O LORD God of hosts, how long will you be angry with your people’s prayers?