I am past thirty, and three parts iced over.

-Arnold, Matthew
  Letter to  Arthur Hugh Clough,12 Feb

Between thirty and forty a man may have reached the height of discretionwithout having tumbledover thetop and into the feather-bed of correctitude.

-Bennett, (Enoch) Arnold
  In the Evening Standard, 29 May.

And I said unto them, If ye think good, give me my price; and if not, forbear. So they weighed for my price thirty pieces of silver.

-Bible (Old Testament)
Zechariah11:12.

Then one of the twelve, called Judas Iscariot, went unto the chief priests, And said unto them,What will ye give me, and I will deliver him unto you? And they covenanted with him for thirty pieces of silver.

-Bible (NewTestament)
St Matthew 26:14^15.

'I've never been spoken to like this before in all my thirty years'experience,'she wails.'You have not had thirty years'experience,Mrs Grindle-Jones,' he says witheringly. 'You have had one year's experience 30 times.'

-Carr,J(ames) L(loyd)
  The Harpole Report, ch.21.

  The faces of most American women over thirtyare relief maps of petulant and bewildered unhappiness.

-Fitzgerald, F(rancis) Scott Key
  Letter, 5 Oct.