This poem, unusual in that the first-person narrator is declaring an association to beauty, is both a salute to the Rhodora’s beauty and a declaration that the narrator is of the same stuff.  It creates a moral universe in which even the plainest observer of Beauty is entitled to the same blessings as the flower, “rival of the rose.”  And just as the rhodora has its season, and is to be found in remote places, out of public display, it can still be appreciated by those who find it in private scenes and recognize its beauty.  When the poet is asked “Whence (from where) is the flower?” the response is  "Beauty is everywhere" – “Beauty is its own excuse for being.”  The narrator, far from questioning why the flower existed, supposed that the Creator who made this flower, this beauty, made the narrator also.  So the dramatic “lesson to be learned” is that the very fact of Creation is beautiful, and we are all part of it–thus, we are all beautiful.  The rhodora was there in Nature to please the desert, the brook, even the red-bird whose beautiful plumage is “cheapened” by the flower’s beauty.  In this age, when social pressure is on everyone to be “attractive,” this poem gives a wise response.