The day is thine, the night also is thine: thou hast prepared the light and the sun.
The day is thine. Not only the sea and the waters, but the day and the light are at thy sovereign control. Not only in history, but also in creation and in providence, God reigns.
Thou hast prepared the light and the sun. Science confirms revelation that light and the light-bearing body are distinct (Genesis 1:3; Genesis 1:14-16). Maa'owr (H3974) is literally a luminary or light-bearing body (Genesis 1:14). Shemesh (H8121) is the solar stream of light from it (cf. Joshua 10:12, which is explained by this consideration).