Fifty years ago Sunday — Christmas Eve 1967 — the Rev. Dr. Martin Luther King Jr. stood in his pulpit at Ebenezer Baptist Church in Atlanta and told the congregation that in order to achieve peace on earth, “we must develop a world perspective,” a vision for the entire planet. “Yes,” he said, “as nations and individuals, we are interdependent.” Then, with a sentence that could easily have been uttered by John Muir or Rachel Carson, Dr. King stated, “It really boils down to this: that all life is interrelated.”

Best remembered for his work and speeches on civil rights, Dr. King on that morning, in his last Christmas sermon before his assassination, anticipated much of the ecological consciousness and environmental concerns of the next 50 years, and the links between ecology and social justice that are vital to our present and future. Dr. King’s work to dismantle white supremacy and economic injustice was rooted in his prophetic Christianity, shaped by the black radical tradition, the Social Gospel and the black freedom struggle. Less known is his understanding of existence as unified and the voice he gave to a cosmology of connection.

In the last years of Dr. King’s life, his holistic vision led him to emphasize the connections between racism, militarism and economic injustice, and to see continuities across social movements. In a 1966 telegram to the labor leader Cesar Chavez, he wrote, “our separate struggles are really one.” Three weeks after his Christmas sermon, Dr. King visited the singer Joan Baez in jail, following her arrest after a sit-in at a draft induction center. Stopping to speak with Vietnam War protesters gathered outside, he told them, referring to civil rights and antiwar activism, “I see these two struggles as one struggle.”

Dr. King was not, as some charged, calling for what he termed a “mechanical fusion” of the peace and civil rights movements. Still, he maintained, the issues were connected, telling his staff that racism, militarism and excessive materialism are “inseparable triplets.” In Dr. King’s mind, the civil rights movement was part of a broader “revolution of values” that was “forcing America to face all its interrelated flaws.” As he put it, what we need is nothing less than “a restructuring of the very architecture of American society.”