Who is Professor Abraham Joshua Heshel from A Testament of Hope: The Essential Writings and Speeches of Martin Luther King, Jr and what is their importance?

Professor Abraham Joshua Heshel was a Rabbi, who participated in many of the struggles and marches with the civil rights movement. He joined the march from Selma to Montgomery, and he participated in the Chicago for the Conference on Religion and Race. Heshel did not hide behind his religion, but stood beside the leaders.