When the going gets tough, the tough get going (1961)

[Bapopik at AOL.COM]

   Lots of other forms are close.  Try this:

   24 January 1943, WASHINGTON POST, pg. R5:
_Hornsby Sharp in Criticism_
_Of Would-Be Baseball Quitters_
(...)
   "When the going get tough is the time to do your hardest fighting.  Anybody can sail along when there's nothing to interfere and everything is bright and sunshiny.  What if we do lose some money.  It won't be the first time.  But we ought to keep the game going."