Answer:
The daffodils are dancing! Not literally, of course, since this is personification. Wordsworth sees nature as beautiful and light, like how a dancer would be. It shines light on the good of the world, in the form of making something as non-human as a flower have more human qualities.
Step-by-step explanation:
By "human qualities" I mean things like dancing, singing, holding objects, talking, whispering, etc.