William Blake's "Auguries of Innocence,"

"To see a world in a grain of sand,
And a heaven in a wild flower,
Hold infinity in the palm of your hand,
And eternity in an hour."

1.What does the stanza mean?
I think this stanza means that the world is beautiful and one should enjoy it to the fullest doing what one likes to do/living the moment and loving every minute of it day by day because nobody knows what can happen in an hour. One sees infinity but never sees eternity. Therefore one should live as if their was no tomorrrow.

2.How does Blake use a literary device to convey that meaning?
 Blake uses methapor in the first line "To see a world in a grain of sand" because he is comparing the world to a grain of sand meaning to enjoy it.

I think he also uses Symbol in te line "Hold infinity in the palm of your hand" because how can u hold infinty in the palm of ur hand its just an idea for u to keep on with life thinking ahead having a goal to reach.