Was ist das Schwerste von allem?
Was dir das Leichteste dünket,
mit den Augen zu sehen,
Was vor den Augen dir liegt.

What is the most difficult of all?
That which seems to you the easiest,
To see with one’s eyes
that which is lying before them.

—Goethe, Xenien Aus Dem Nachlass #45
Found in: Lexikon der Goethe Zitate.