The psalm begins with a brief declaration: the Lord reigns. He is robed in majesty and strength, like one putting on a garment, and he has established the world, which will not be moved. God does not begin to reign at some moment: his throne has stood firm from of old and he exists from all eternity.
Then the poem presents a threat. The floods lift up their voice, the floods lift up their roaring, the waves pound. The peoples of the ancient world saw deep waters as a picture of chaos and hostile forces, and the psalm acknowledges them with their noise. But the Lord on high is mightier than the thunders of many waters and the mighty breakers of the sea.
The psalm ends by returning to earth and to the house of God. His decrees are very sure, and holiness befits his house, O Lord, for evermore.