“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?”

Variants (Many of MLKs' speeches were delivered many times with slight variants): 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?'
As quoted in The Words of Martin Luther King, Jr. by Coretta Scott King, Second Edition (2011), Ch. "Community of Man", p. 3
1950s, Conquering Self-centeredness (1957)

Source: The Story of My Life and Work

1950s, Conquering Self-centeredness (1957)
Context: I look at my little daughter every day and she wants certain things and when she wants them, she wants them. And she almost cries out, “I want what I want when I want it.” She is not concerned about what I think about it or what Mrs. King thinks about it. She wants it. She’s a child and that’s very natural and normal for a child. She is inevitably self-centered because she’s a child. But when one matures, when one rises above the early years of childhood, he begins to love people for their own sake. He turns himself to higher loyalties. He gives himself to something outside of himself. He gives himself to causes that he lives for and sometimes will even die for. He comes to the point that now he can rise above his individualistic concerns, and he understands then what Jesus meant when he says, “He who finds his life shall lose it; he who loses his life for my sake, shall find it.”’ In other words, he who finds his ego shall lose his ego, but he who loseth his ego for my sake, shall find it. And so you see people who are apparently selfish; it isn’t merely an ethical issue but it is a psychological issue. They are the victims of arrested development, and they are still children. They haven’t grown up. And like a modern novelist says about one of his characters, “Edith is a little country, bounded on the east and the west, on the north and the south, by Edith.” And so many people are little countries, bounded all around by themselves and they never quite get out of themselves. And these are the persons who are victimized with arrested development.

Source: Kierkegaard’s Critique of Reason and Society (1992), p. 38

Al-Isti'ad li Yawm al-Mia'd, p. 9

1980s
Context: If you are not at all concerned with the world but only with your personal salvation, following certain beliefs and superstitions, following gurus, then I am afraid it will be impossible for you and the speaker to communicate with each other. …We are not concerned at all with private personal salvation but we are concerned, earnestly, seriously, with what the human mind has become, what humanity is facing. We are concerned as human beings, human beings who are not labelled with any nationality. We are concerned at looking at this world and what a human being living in this world has to do, what is his role?

Diwali does not end when the lights go out (2013)
Context: Hindus have a deep religious responsibility to be politically engaged. At the heart of this engagement must be a concern for the well-being of all. We ought to ensure that Hindus are known, in whatever part of the world we reside, Asia, Europe, Africa, North America and the Caribbean, for our commitment to overcoming suffering rooted in poverty, illiteracy, disease and violence. This commitment must become synonymous with what it means to be Hindu in our self-understanding and in the eyes of others. Politics, according to Mahatma Gandhi, is concerned with the well-being of human communities and anything concerned with human well-being must concern the person of religious commitment. Gandhi was deeply inspired by the life of Rama and especially by the nature of the community established after Rama's return from exile. He understood his life's purpose as working with others to make this community a reality.
Unfortunately, our religious traditions are known more for what we stand against than what we stand for. Religious identity has become negative rather than positive. We need to ensure that the positive dimension of our commitment is more prominent than the negative.
Let us celebrate Diwali, the festival of lights, with joy. Let each celebration, however be a reminder and renewal of our profound obligations to help bring the lights of prosperity, knowledge, health and peace to our communities, nations and our world.

Source: Epistemics and Economics. (1972), p. 150-1