Commentaries:
Note David's mention of “[H]is clouds.” Numbers 10:34 refers to “the cloud of the LORD.” The clouds God rides (compare Psalm 68:4) are unique for at least two awe-inspiring reasons.
First, unlike the rainy-day clouds we experience so often (scientifically, the colloidal aerosol made up predominately of water vapor), God's clouds issue “coals of fire” as well as moisture. God's clouds are supernatural. They are in some ways like the clouds we know so well—the clouds that testify to God's power and divinity—but in other ways astonishingly different.
Second and more importantly, God's clouds reflect His glory. We might say God's clouds are a lens focusing His glory. When God's clouds are around, He is around! His clouds signal His presence.
Charles Whitaker
Clouds (Part One): A Really Special Cloud