What does Psalm 93:1 mean?

That God is "robed" or "clothed" or "girded" with something means that it is an obvious aspect of His nature. In this case, the psalmist credits God with power and magnificence. All that happens in creation is under His control. The English word "sovereign," in fact, adapts an older word meaning "above" to match the spelling of "reign." God rules—reigns—above all things. His throne—the concept of His absolute authority (Psalm 93:2)—is beyond dispute.

Also mentioned is that the Lord has created: He has "established" all that exists. In this context, "the world" would imply both the physical earth and all its people. These are firmly grounded in God's sovereign control. They cannot be undone or altered apart from His permission. God is so powerful that He can speak things into existence (Genesis 1:1; Hebrews 11:3). What He creates He also controls, and that power is not subject to anyone or anything else.