A quotation by Leopold Kronecker
Number theorists are like lotus-eaters - having tasted this food they can never give it up.
Quoted in H Eves Mathematical Circles Squared (Boston 1972).
Die ganzen Zahlen hat der liebe Gott gemacht, alles andere ist Menschenwerk.
God made the integers, all else is the work of man.
From Weber's obituary of Kronecker
See THIS LINK.
What good your beautiful proof on [the transcendence of] π? Why investigate such problems, given that irrational numbers do not even exist?
Addressed to Lindemann