Martin Luther King Jr. put the pages of his speech down and pushed them over to his left. He grabbed the lectern with both hands and leaned forward. Clarence B. Jones was standing on the steps of the Lincoln Memorial with him on Aug. 28, 1963. “These people out there, they don’t know it,” Jones recalled telling the person standing next to him. “But they’re about to go to church. And that’s when he started his extraordinary speech that we know as the ‘I Have a Dream&rsquo …