So sweet the hour, so calm the time,
I feel it more than half a crime,
When Nature sleeps and stars are mute,
To mar the silence ev'n with lute.
At rest on ocean's brilliant dyes
An image of Elysium lies:
Seven Pleiades entranced in Heaven,
Form in the deep another seven:
Endymion nodding from above
Sees in the sea a second love.
Within the valleys dim and brown,
Not only is the number seven a symbol of perfection, Biblical-wise, the number seven has great significance. From the first chapter of  Genesis 2:2 , God creates the heavens and the Earth in 7 days; down to the last chapter of  Revelation 15:1 , where seven angels and seven plagues are witnessed. In fact, the number seven is mentioned at least 800 times in the whole Bible.
Serenade