Fantastic Beasts: The Crimes Of Grindelwald - 19 Easter Eggs & References Explained
4. "For The Greater Good"
When Grindelwald attempts to confirm the favour of his followers ahead of the film's final battle, he uses the phrase "for the greater good" in respect to humanity's self-destructive tendencies.
The phrase first appears in the novel of The Deathly Hallows, in a letter from Dumbledore to Grindelwald, where he warns his pal that holding dominion over humans should only be done for, yes, the greater good.
The phrase also appears in the book when Dumbledore’s brother Aberforth debates the utility of the greater good with Harry while discussing his sister Ariana's accidental death.
Following Grindelwald's involvement in her demise - being part of a three-way duel which saw her caught in the crossfire - the wizard tyrant solely adopted the phrase as a mission statement for his quest for muggle domination, and the rest is history.