Source: As quoted by Coretta Scott King in The Words of Martin Luther King, Jr.: Second Edition (2011), Ch. “Community of man”, page: 3.

Complete Sentence: An Individual has not started living fully until they can rise above the narrow confines of individualistic concerns to the broader concerns of humanity. Every person must decide at some point, whether they will walk in light of creative altruism or in the darkness of destructive selfishness. This is the judgment: Life’s most persistent and urgent question is: ‘What are you doing for others?’