Transcript for Remembering and honoring Dr. Martin Luther King Jr.
Finally tonight, Dr. Martin Luther king Jr. Once said life's most persist end and urgent question is, what are you doing for others? Across the country today, for so many Americans, it was a day to serve. Penn state students repairing by Sickles for neighborhood children. In North Carolina, stocking a food pantry. Volunteers serving breakfast in Harlem. In Pittsburgh, this 7-year-old girl and her finishing touches on a blanket for meals on wheels. And in Chattanooga, Tennessee, new growth in honor of Dr. King. This was Dr. Martin Luther king jr.'s final Sunday sermon at Washington national cathedral. His life would be taken four days later. And this is what he said. It may well be that we will have to repent in this generation, not merely for the vitriolic words and the violent actions of the bad people, but for the appalling silence and indifference of the good people who sit around and say, "Wait on time." Reporter: His words, a warning about silence, about indifference. And so however dark it is, however deep the angry feelings are, the violent explosions are, I can still sing "We shall overcome." We shall overcome, because the arc of the moral universe is long, but it bends towards justice. Dr. Martin Luther king Jr. I'm David Muir. I hope to see you tomorrow. Good night.
This transcript has been automatically generated and may not be 100% accurate.