Night is the main character here. The speaker watches the moon rise after the sun has gone and pictures it as a silver knight in armor, guarding the dark. The light feels almost physical: it flows like a creek and swirls around the speaker's fingers. The wish to keep it in a jar is the most personal moment, a small, childlike longing to hold onto something beautiful that hangs so far away in a "lonely sky."
Then the poem turns from sight to sound. The world slows down, the crickets chirp, and the busy day settles into rest. The speaker imagines silence itself playing a tune, one that is calm, gentle, and wise, whispering peace to "uneasy minds." That phrase hints the speaker may be a little restless or worried, and finds comfort in the night. The mood is soothing and dreamy, like a lullaby, ending with the moon singing until the sun returns to "relight his kingdom."