Psalm 74:12–17 is a proclamation of God’s kingship over the earth and a reminder of the early history of the covenant. The psalmist probably lived in the sixth century BC, which means that he was describing events that happened a thousand years before, when God established his covenant with his people and became their King. This verse is an announcement that summarizes the second part of the psalm.
12 Yet God my King is from of old, working salvation in the midst of the earth.