What tone does Martin Luther King, Jr. create through his choice of words in the following portion of his Nobel Prize acceptance speech?

I accept the Nobel Prize for Peace at a moment when 22 million Negroes of the United States of America are engaged in a creative battle to end the long night of racial injustice, I accept this award on behalf of a civil rights movement which is moving with determination and a majestic scorn for risk and danger to establish a reign of freedom and a rule of justice. I am mindful that only yesterday in Birmingham, Alabama, our children, crying out for brotherhood, were answered with fire hoses, snarling dogs and even death. I am mindful that only yesterday in Philadelphia, Mississippi, young people seeking to secure the right to vote were brutalized and murdered. And only yesterday more than 40 houses of worship in the State of Mississippi alone were bombed or burned because they offered a sanctuary to those who would not accept segregation. I am mindful that debilitating and grinding poverty afflicts my people and chains them to the lowest rung of the economic ladder.