Try not to become a man of success but rather try to become a man of value.[Versuch nicht, ein Mann des Erfolgs zu werden. Werde lieber ein Mann von Wert!]
Source:Death of a Genius: His fourth dimension, time, overtakes Einstein, Subsection: Old Man's Advice to Youth: 'Never Lose a Holy Curiosity' by William Miller in Life Magazine (May 2, 1955)