The Rev. Martin Luther King Jr. was dozing off in his bedroom around midnight when the phone rang.

“Listen, n**&**r, we’ve taken all we want from you,” a caller hissed. “Before next week, you’ll be sorry.”

King hung up and walked to his kitchen to heat a pot of coffee. He had been receiving death-threats for weeks - ever since he had accepted a request to lead African-Americans during a bus boycott in Montgomery, Alabama.

But King was starting to doubt his decision.

As the threats poured in, his fears increased for his wife, Coretta, and their infant daughter, Yolanda. He now wondered how he could relinquish his role as the boycott leader without appearing a coward.

Then something happened that King would talk about for years afterward. He bowed over his untouched cup of coffee, and prayed aloud in desperation. King said he heard an “inner voice” that addressed him by name, and encouraged him to stand up for justice.

King’s kitchen table prayer is part of what inspired Lewis V. Baldwin to write, “Never to Leave Us Alone: The Prayer Life of Martin Luther King Jr.”

Baldwin, a religious studies professor at Vanderbilt University in Tennessee, says most people know King as the great public orator, but few know about his rich prayer life.

King crafted “some of the most strikingly and profoundly moving prayers in all of sacred literature.” Baldwin said. His kitchen table plea may have been his most important prayer.

“It was a conversion experience for Dr. King,” Baldwin said. “King never had what, in the language of the church, is called ‘a crisis conversion.’ "

Baldwin recently talked with CNN about King’s prayer life. His remarks were edited for brevity.

CNN: What inspired you to examine Dr. King's prayer life?

Baldwin: I have been interested in King's spirituality since the early 1980s, because I think we best understand him as a person of faith who translated certain kinds of spiritual and moral values into efforts for social change. So much has been written about King's preaching and pulpit style… but strangely enough, scholars who have treated these subjects ignore King's prayer life.

CNN: Why was King’s kitchen prayer in Montgomery so pivotal for him?

Baldwin: The experience reminded King that he could not depend on the resources of his talents and intellectual training to make it in the struggle. He came to see more clearly that religion had to be real to him in a special way as he confronted the pressures of the movement.

After the kitchen experience, King felt a special divine companionship, or what he called cosmic companionship, and this sustained him. Fear left him and he was assured that if he continued to stand up for justice and righteousness, God would be with him.

CNN: Did praying help prepare King for his long stints in jail?

BALDWIN: Most definitely. As I point out in “Never to Leave Us Alone,” King was often in a prayerful mood. This prayerful mood was most evident when he was struggling with some special challenge. During the civil rights movement, jail cells were often turned into sacred space for what were essentially revival meetings.

King and his aides sang and prayed in jail, calling to mind Paul and Silas. Great prayer meetings occurred in jail cells. I am convinced that prayer and meditation preceded the writing of the Birmingham Jail Letter, and that King wrote it in a prayerful mood. After all, it was a letter from a pastor to pastors.

CNN: Did King ever get so emotional during public prayers that he could not finish?

BALDWIN: This most certainly happened in Montgomery during the bus boycott in 1955. Surrounded by people who were constantly responding to his preaching and praying with shouts of "Amen," "Hallelujah," "Praise God," it was very difficult for King not to get emotional.

His emotions came out that night because he felt some guilt and responsibility as he thought about the bombing of homes and churches that were occurring.

As a boy, King was ashamed of the shouting and other expressions of emotionalism in southern black churches, but he overcame that in his adult life and came to a deeper appreciation of the rich emotional heritage of black churches.

CNN: Was public prayer just as important as freedom songs were in fortifying King and other civil rights leaders?

BALDWIN: When people wanted to take control of their sacred space, they sang and prayed. This happened when sheriffs and constables entered black churches during mass meetings, or when the protesters confronted mobs and symbols of segregation in the streets.

One cannot talk about prayer and songs separately; they were one in the consciousness of those who felt that God was on their side, and who were inspired by the church.