Martin Luther King, Jr was a third-generation pastor. This had a profound effect on his involvement in the civil rights movement, which was, at least until the late 1960s, centered on African-American churches. Like his grandfather and father before him, he served as pastor of the Ebenezer Baptist Church in Atlanta. He was thus accustomed from a young age to positions of community leadership. His academic training for the ministry also exposed him to important ideas that would inform his approach to the struggle for civil rights. Many of his early divinity professors were (more so than King's father) outspoken advocates for racial equality, which they viewed as a moral imperative. King's belief that injustice could not be tolerated in a democratic and moral society was rooted in his understanding of Christianity. In graduate school, he also read the works of Henry David Thoreau, Mahatma Gandhi, and theologian Reinhold Niebuhr. Thoreau and Gandhi advocated peaceful civil disobedience against laws that they deemed unjust. Niebuhr argued that pursuing social justice among human beings was a Christian imperative. King's speeches, sermons, and writings are laden with references to these men and others, speaking to the influence of his religious background on his civil rights work. Had he not been encouraged to pursue the ministry by his father, his life, and indeed American history, might have been much different.