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. But from what I see I am sure it bends towards justice. — Theodore Parker, 1857
A version of this,
The arc of the moral universe is long but it bends toward justice.
is often attributed to Martin Luther King Jr., but as discussed here, he put it in quotations in his written speeches, indicating that he was using it from elsewhere.
