The Lesson

This is the lesson I have learned of Beauty:
Who gathers flowers finds that flowers fade:
Who sets love in his heart above his duty
Misses the part for which that love was made.
Than passion, haply, there is nothing madder:
Who plucks its red rose plucks with it a thorn:
More than soul's pain what hurt can make us sadder?
And yet of this immortal things are born.