In April 1963, Martin Luther King Jr. was arrested for his participation in the organized, non-violent marches and sit-ins against racial segregation in Birmingham. On the same day, eight white Alabama clergymen, some Christian, some not, published an open letter on unity that decried the demonstrations and urged patience, asking people to restrict their efforts to the courts and not the streets. King received a copy of the letter while in prison and in response wrote what is now recognized as one of the most important moral treatises of the 20th century, his famed “Letter from Birmingham Jail.” In it, King damningly exposed the weakness, moral turpitude, and short-sightedness of the “white moderates” encouraging the protesters to cease their activist efforts until a “more convenient season.” It is passionate testimony to King’s deep moral logic, striking in its clarity.

But many engaged in school readings and college composition discussions fail to see that if there is no God, this letter is meaningless.

Arc of the Moral Universe

King was fond of saying that the “arc of the moral universe is long, but it bends towards justice.” It was simultaneously a call to patience and hope on the part of his long-suffering brothers and sisters, as well as a dire warning towards those working against the grain of moral reality. While there may be superficial disobedience to the law in some of the civil rights activism, he explained it is justified by obedience to a deeper, moral law:

One may well ask, “How can you advocate breaking some laws and obeying others?” The answer is found in the fact that there are two types of laws: there are just laws, and there are unjust laws. I would agree with St. Augustine that “An unjust law is no law at all.”

So what is the difference between the two? How does one determine when a law is just or unjust? A just law is a man-made code that squares with the moral law, or the law of God. An unjust law is a code out of harmony with the moral law. To put it in the terms of Thomas Aquinas, an unjust law is a human law not rooted in eternal and natural law. Any law that uplifts human personality is just. Any law that degrades human personality is unjust.

Here we find no appeal to a thin, pragmatic account of rights-based egalitarian liberalism. This is a philosophically, and indeed, theologically thick appeal to a divinely ordered and sustained cosmos. King grounds his argument in the eternal law of God, which gives shape to moral reality. In other words, God bent the moral arc of universe into its particular shape. King elaborates:

All segregation statutes are unjust because segregation distorts the soul and damages the personality. It gives the segregator a false sense of superiority and the segregated a false sense of inferiority. To use the words of Martin Buber, the great Jewish philosopher, segregation substitutes an “I – it” relationship for the “I – thou” relationship and ends up relegating persons to the status of things. So segregation is not only politically, economically, and sociologically unsound, but it is morally wrong and sinful. Paul Tillich has said that sin is separation. Isn’t segregation an existential expression of man’s tragic separation, an expression of his awful estrangement, his terrible sinfulness? So I can urge men to obey the 1954 decision of the Supreme Court because it is morally right, and I can urge them to disobey segregation ordinances because they are morally wrong.

Lest the point be lost amid appeals to Buber and Tillich, King tacitly relies on the created dignity of the human person, made in the image of God. For King, segregation is not only sociologically suicidal but morally sinful. It violates our created nature and the eternal law of God. But where there is no law, there is no sin.

Despite the best efforts of secular admirers (see Christopher Hitchens), it is simply impossible to separate King’s denunciation of racism and segregation from his Christian confession and theological convictions about the nature of the universe. Absent a creator God who ordered the moral universe, the “arc” is no more than a sort of elevated survival instinct, our inevitably shifting social conscience, or some Platonic abstract ideal (a toothless law without a lawgiver).

By common grace some people will be motivated by these alternate principles, at least for a time. Eventually philosophical incoherence catches up. Then these moral foundations simply cannot sustain the needed, long-term struggle for justice that King and his associates engaged in. For peaceful, passionate, and determined protest, we need to be persuaded that we are tapping into moral bedrock of reality—one subject to the vindication and redemption of its Creator.


As a final instructive exercise, I’ve excerpted a number of key passages from the letter and excised any mention of God. Feel free to fill them in with whatever substitute you like (society, biological nature, and so on). It is impossible to read them and not feel the gaping hole it leaves in the beauty, weight, and power of King’s appeal.

We have waited for more than 340 years for our constitutional and _______given rights.

A just law is a man made code that squares with the moral law or the law of_______.

Human progress never rolls in on wheels of inevitability; it comes through the tireless efforts of men willing to be co workers with______, and without this hard work, time itself becomes an ally of the forces of social stagnation.

Whenever the early Christians entered a town, the people in power became disturbed and immediately sought to convict the Christians for being “disturbers of the peace” and “outside agitators.” But the Christians pressed on, in the conviction that they were “a colony of heaven,” called to obey________rather than man. Small in number, they were big in commitment. They were too _________intoxicated to be “astronomically intimidated.” By their effort and example they brought an end to such ancient evils as infanticide and gladiatorial contests.

But the judgment of________is upon the church as never before. If today’s church does not recapture the sacrificial spirit of the early church, it will lose its authenticity, forfeit the loyalty of millions, and be dismissed as an irrelevant social club with no meaning for the twentieth century.

If the inexpressible cruelties of slavery could not stop us, the opposition we now face will surely fail. We will win our freedom because the sacred heritage of our nation and the eternal will of_______are embodied in our echoing demands.

They will be the young high school and college students, the young ministers of the gospel and a host of their elders, courageously and nonviolently sitting in at lunch counters and willingly going to jail for conscience’ sake. One day the South will know that when these disinherited children of_____sat down at lunch counters, they were in reality standing up for what is best in the American dream and for the most sacred values in our Judaeo Christian heritage, thereby bringing our nation back to those great wells of democracy which were dug deep by the founding fathers in their formulation of the Constitution and the Declaration of Independence.