Obama’s own fresh contribution to the genre is his invocation of “the arc of history.” It’s his adaptation of an older phrase, “The arc of the moral universe is long but it bends toward justice,” which was popularized by Martin Luther King Jr. but coined (evidently) a century earlier by Theodore Parker. Obama has mentioned “the arc of history” a dozen times since his election.
https://www.theatlantic.com/politics/archive/2015/12/obama-right-side-of-history/420462/