Almost 40 years after his death, the Rev. Martin Luther King Jr. and his vision continue to provide hope and inspiration to the world. Marian Wright Edelman -- activist and winner of the Albert Schweitzer Prize for Humanitarianism -- offers reflections on her mentor's life and message based on their friendship. In this article, Edelman lends insight into King's definition of service, and encourages readers to celebrate the yearly American holiday as "a day on, not a day off," using his birthday to come together for community service and action.