And hesaiduntothem,Outoftheeatercameforthmeat, and out of the strong came forth sweetness. And they could not in three days expound the riddle.

-Bible (Old Testament)
Judges14:14.

If ye had not plowed with my heifer, yehad not found out my riddle.

-Bible (Old Testament)
Judges14:18.

I cannot forecast to you the action of Russia. It is a riddle wrapped inside a mystery inside an enigma.But perhaps there is a key; that key is Russian national interest.

-Churchill, Lord Randolph Henry Spencer
  Radio broadcast,1 Oct.

Can I expound the skies? How still the Riddle lies!

-Dickinson, Emily Elizabeth
c.1859  Complete Poems, no.89 (first published1890).

Created half to rise, and half to fall; Great lord of all things, yet a prey to all; Sole judge of truth, in endless error hurled; The glory, jest, and riddle of the world!

-Pope, Alexander
  An Essay on Man, epistle 2, l.15^18.