The speaker is reflecting on the limits of human control. We cannot give ourselves every honor or achievement, and we cannot coax fate into fighting on our behalf. No matter who we are or what kind of beauty or truth we create—what we sing—time will always find something faded or flawed in our successes. The laurel wreath, the old symbol of victory and poetic fame, still contains a withered leaf. The feeling is not angry or bitter; it is calm, slightly sad acceptance. The mood is quiet, autumnal, and honest: a reminder that even our best accomplishments are temporary and imperfect, and that this is simply part of being human.
Three Quatrains III — Summary
We cannot crown ourselves with everything, Nor can we coax the Fates for us to quarrel: No matter what we are, or what we sing, Time finds a withered leaf in every laurel.