On the surface, this may seem a strange question. After all, it is fairly well known that King was a Baptist minister. Moreover, his public speeches were full of quotations from the Christian scriptures. His political philosophy of resisting evil through non-violence seems consistent with Jesus' warning in Matthew 26:52 that those who draw the sword will die by the sword and Jesus' own example of not resisting those who sought to arrest and kill Him.
Nevertheless, controversary remains as to whether King was actually a theologically orthodox Christian. This is at least in part due to some of King's writings as a young man, when studying at Crozer Theological Seminary. According to Joe Carter of the Gospel Coalition, "in a paper he wrote for a systematic theology class [King] cast skeptical aspersions on the doctrines of [the divine Sonship of Jesus], the Virgin Birth...and the Resurrection." In another paper written when he was a seminary student, King asserted that "fundamentalists" are "willing to preserve ancient ideas even though they are contrary to science" (as quoted by Carter). Similarly, in an article on a posthumously-discovered collection of King's writings, Matthai Chakko Kuruvila claims that King "rejected a Biblical literalism."
On the other hand, in the same article, Kuruvila quotes Jim Wallis, the prominent political progressive who also identifies as an evangelical Christian, who asserts that "King's faith moved beyond the liberal theology of his youth and deepened as the civil rights struggle intensified." In fact, King would eventually write that he had come to realize that "liberalism had been all too sentimental about human nature and that it leaned toward a false idealism. I also came to see that liberalism's superficial optimism concerning human nature had caused it to overlook the fact that reason is darkened by sin" ("Pilgrimage to Nonviolence" by Martin Luther King, Jr., Christian Century 77 (April 1960)). According to Tyler Helfers, "much of this [realization] came to light through King's study of [American theologian] Reinhold Niebuhr and the neo-orthodox movement." The neo-orthodox movement is sometimes referred to as neo-orthodoxy. What is neo-orthodoxy? According to gotquestions.com:
Neo-orthodoxy defines the Word of God as Jesus (John 1:1) and says that the Bible is simply man's interpretation of the Word's actions. Thus, the Bible was not inspired by God, and being a human document, various parts of it may not be literally true. God spoke through "redemptive history," and he speaks now as people "encounter" Jesus, but the Bible itself is not objective truth.
However, according to Helfers, despite the impact of neo-orthodoxy on King's thinking, "King could not completely give himself theologically and intellectually over to neo-orthodoxy. Instead, he sought a 'third way' that synthesized the 'truths' of both [liberalism and neo-orthodoxy]: reason and experience, love and power, tangible and spiritual."
Yet another view about the nature of King's faith comes from Aaron Campbell. Writing at calvarychapel.com, Campbell discusses an "obscure essay [King] once wrote about the night back when he was leading his first bus boycott for the desegregation of buses in Montgomery, Alabama, and in retaliation, someone shot up his house, leaving bullet holes in the very sanctuary his wife and kids found refuge." According to Campbell, "shaken to his core by what had happened to his home, [King] asked himself if he had truly experienced a (spiritually) born again experience in making Jesus Christ his personal Lord and Savior." Consequently, "not sure his own answer to that question, but wanting to be sure he was truly 'in Christ'...[King] actually lowered his head and invited the risen Christ into his heart as his personal Lord and Savior for the remission of sins." In effect, Campbell appears to be saying, King became a "born again" or evangelical Christian.
It should also be acknowledged that another reason for doubts about King's Christian faith are some problematic aspects of his personal life, including a number of incidences of marital infidelity. However, to be fair, a failure to live up to the Biblical standard of faithfulness in marriage is not necessarily evidence of a lack of genuine faith (witness, for example, King David)--although it is certainly not something that should be minimized or excused since it is clearly sin.
In short, we are left with at least three possible answers to the question of Martin Luther King Jr.'s faith. Depending on which view you find most credible, King was either a theological liberal who rejected historic Christian beliefs, or someone whose beliefs straddled liberalism and neo-orthodoxy, or a "born again" Christian. Unfortunately, there is probably no way we can know for certain, this side of Heaven, which of these is correct. Of course, regardless of what he believed, the importance of King's role in the struggle for racial justice in America can never be doubted. Nevertheless, I would suggest to my fellow Christians that, as is the case with other important figures in American history (e.g., George Washington and Abraham Lincoln), we need to be cautious about claiming King as one of our own.
Image of Dr. Martin Luther King, Jr. from Wikimedia Commons