That Martin Luther King Jr. bore the name of Martin Luther is the most obvious link between them. But the influence of the German reformer on the American civil rights leader was more profound than that.
When Martin Luther King Jr. brought his civil rights campaign to Chicago, then the US's second largest city, in the summer of 1966, he took a page out of his German namesake's book and attached his demands for fair and open housing to the door of city hall.
The episode is one of a few instances when Martin Luther King himself directly evoked Martin Luther, who famously is said to have posted his 95 theses that challenged Catholic doctrine to the door of the castle church in Wittenberg in 1517.
Read more: Martin Luther's daring revolution
The most obvious connection between King and Luther — the fact that King bore the German reformer's name — greatly influenced him. It did not, however, not stem from King himself, but from his father, Martin Luther King Sr.
There are differing accounts as to whether the older King, who was born Michael King, chose to rename himself and his son Michael Jr, upon his return from a Baptist conference in Berlin in the 1930s, where he had been impressed by the late German reformer, or whether — as the elder King told a New York newspaper in 1957 — he was renamed by his own father and decided to bestow the name on his son, too. In any case, while both Kings became known publicly by the new moniker, the name change was apparently never recorded in official documents, and the two continued to be known in the family as Little Mike and Big Mike.
Another instance in which King deliberately invoked his namesake was his letter from a Birmingham jail. Here King quotes Luther's famous dictum, "Here I stand; I cannot do otherwise, so help me God," alongside references to other historic figures like Abraham Lincoln and Thomas Jefferson. Otherwise, though, the pastor from Georgia rarely quoted the German, said Richard Lischer, professor emeritus of preaching at Duke University and the author of "The Preacher King: Martin Luther King Jr. and the Word that Moved America."
Still, the German reformer's influence on King, who was not a scholar of Lutherism, was profound, if largely indirect, said Lischer. "I think what he absorbed from Luther was a sense of courage and the freedom to defy authority. Where Luther of course defied religious authority, King defied cultural and political authorities."
Taking a stand
For Mark Noll, professor emeritus of history at Notre Dame University and a noted scholar of Christianity in the United States, Luther's fateful journey to Worms to defend the charges of heresy against him almost 500 years ago influenced King's stance against racism in the 1950s and 1960s.
"The willingness of Martin Luther to stand before the emperor Charles V at Worms in 1521 in some sense was an inspiration for the civil rights leaders, Martin Luther King Jr. and others, to stand forthrightly against centuries of segregation tradition and to proclaim what they thought was not just an ethical truth, but the word of the Lord."
Both preachers were also connected through a deep knowledge of the scriptures and the conviction that their battle against the authorities had to be waged peacefully, a condition whose importance is difficult to overstate.
While Luther and King thus shared several essential traits — like their willingness to confront authority to follow what they believed was God's will, even at the risk of grave personal consequences — on a more detailed theological level, there were clear differences.
"For Luther the redemptive moment is first of all very personal in the cross of Jesus. For King it is more corporate and he finds God working through the exodus from Egypt and the deliverance of all people from captivity," said Lischer.
That's hardly surprising given the broader Christian ethic held by Luther and King also differed significantly. Luther, explained Noll, built his ethic upon the doctrine of the two kingdoms in which the church is the place for the people to hear God's message of reconciliation and the governmental sphere is the place where the Lord has given rulers authority which must be obeyed by society, even if people suffer unjustly because the rulers were God's servants for maintaining peace in the world.
"That is obviously a very different ethic that Martin Luther King held when he felt that there was something amiss in society," said Noll. "When he felt there was something amiss, something evil in society, it was the duty of a moral person and a pastor to directly challenge the injustice that he saw in society and to work in all possible means to change that society."
Read more: Preachers of prosperity: faith as business
Given King's view of a Christian's role in society, he likely would have objected to some of Luther's positions, such as his views of the peasants and the Jews, said Lischer. Generally, he noted, he would have found Luther too quiet in the political sphere. Likewise, the German reformer, who was afraid of disorder, would probably worry about the kind of direct challenge to Obrigkeit, to authority, that Martin Luther King Jr promoted, said Noll.
"But I do think that Martin Luther would appreciate and admire what Martin Luther King did in courageously standing up before authority and saying 'My conscience is captive to the word of God that tells me all people are created equal and that this equal creation needs to be implemented in practice and not just in theory,'" he added.
In different ways and at different times both Luther and King affected profound change.
"Luther achieved a wide-ranging transformation of human thought and in so doing also took away the power of one institution, namely the church of his day to decree what people were and what to expect from God," said Lischer.
"King did change the face of American life, which was no small thing, and he did it in a very short period of time," said Noll. "The America we have today is so different from the America of the 1950s and 1960s with regard to racial freedom."
Relevance for today
Asked about the continued relevance of Luther and King, both scholars argue that the German reformer and the American civil rights leader remain essential moral guides for today.
"As a Christian myself, I think that Martin Luther's message of the need of all people for reconciliation with god is a message that is as relevant today as it was 500 years ago," said Noll. "And I think Martin Luther King Jr. is in many ways just as, or even more relevant, today than he was in the 1960s. Racism has been the United States's original sin and has never been fully and self-consciously addressed as a moral failing of the culture."