Reference: Moroni declares that he is quoting scripture. The phrasing is influenced by Romans 12:19. However, it supplies only “vengeance is mine… I will repay,” a sentence also quoted in Mormon 3:15. That part of the verse is a reference to Deuteronomy 32:35: “To me belongeth vengeance, and recompence.… ”
The first part of what Moroni indicates as scripture, “man shall not smite, neither shall he judge,” does not have a clear referent in our texts. Perhaps it references a scripture from the plates of Nephi that Mormon did not copy into his text.