The first impression is readily received. We are so constituted that we believe the most incredible things; and, once they are engraved upon the memory, woe to him who would endeavor to efface them.

[Der erste Eindruck findet uns willig, und der Mensch ist gemacht, daß man ihn das Abenteuerlichste überreden kann; das haftet aber auch gleich so fest, und wehe dem, der es wieder auskratzen und austilgen will!]

Johann Wolfgang von Goethe (1749-1832) German poet, statesman, scientist

The Sorrows of Young Werther, Book 1, “August 15” (1774) [tr. Boylan]
    (Source)

Alt. trans.:

• "... woe to him who would endeavor to erase them!" [tr. Lange, Ryan]
• "The first impression finds us receptive, and man is so made that he can be persuaded by the most outlandish things; but it strikes root so immediately that woe to him who tries to scratch it out and eradicate it!" [tr. Pike (2004)]
• Original German.