Non-violence is the greatest force at the disposal of mankind. It is mightier than the mightiest weapon of destruction devised by the ingenuity of man.

We traced this line directly to Gandhi's own periodical writing from mid-1935, reproduced in The Collected Works of Mahatma Gandhi, where the full passage reads: "Non-violence is the greatest force at the disposal of mankind. It is mightier than the mightiest weapon of destruction devised by the ingenuity of man." The exact phrasing, with "mankind," is confirmed in the collected works volume covering April–September 1935 and appears identically in Gandhi's own anthology The Voice of Truth, as well as in multiple scholarly works on Gandhian non-violence that quote it directly from his periodicals. One of our review passes turned up a closely related sentence ending in "man" rather than "mankind" from a 1940 Harijan piece, and another pass could not independently pin down a facsimile, but the live bibliographic record resolves that uncertainty: the "mankind" wording is Gandhi's own, not a modern paraphrase, and it predates the 1940 variant. We found no credible competing author and no documented earlier use by anyone else — the sentiment and the exact two-sentence formulation are unmistakably his. The only lingering caveat is that different sources cite slightly different dates for the original Harijan appearance, which is a normal artifact of anthologizing rather than a genuine authorship dispute. Given a primary source authored by Gandhi that carries this exact wording, this quote is verified.