Look at the facts of the world. You see a continual and progressive triumph of the right. I do not pretend to understand the moral universe; the arc is a long one, my eye reaches but little ways; I cannot calculate the curve and complete the figure by the experience of sight; I can divine it by conscience. And from what I see I am sure it bends towards justice.
This portion of Parker's sermon is thought to have inspired Martin Luther King, Jr. 's famous assertion of similar sentiments: "The arc of the moral universe is long, but it bends towards justice". - Ten Sermons of Religion (1853)