A dictionary of Proverbs (Oxford Paperback Reference)

The OPERA isn’t over till the fat lady sings
Attempts to determine the identity of the diva concerned have been inconclusive.

• 
  1978 Washington Post 13 June B1 The opera isn’t over till the fat lady sings. .. One day three years ago, Ralph Carpenter, who was then Texas Tech’s sports information director, declared to the press box contingent in Austin, ‘The rodeo ain’t over till the bull riders ride.’ Stirred to top that deep insight, San Antonio sports editor Dan Cook countered with, ‘The opera ain’t over till the fat lady sings.’ 1988 D. L. GILBERT Black Star Murders viii. As soon as the big blond Briinnhilde finished, it was over. All I could think about was the classic line about the opera never being over until the fat lady sings. 1992 Independent 11 Aug. 7 ‘You know, they say that the show’s never over until the fat lady sings,’ Mr Bolger said. ‘Well, I think it was her we heard warming up in the wings this week.’ 2002 Times 2 July 19 [T]he Royal Opera House’s leading lady whose dress was set on fire by an on-stage candle is a classic case of it ain’t over till the fat lady singes. "finality
  

opinion see he that COMPLIES against his will is of his own opinion still; so many MEN, so many opinions.
OPPORTUNITY makes a thief

• 
  c 1220 Hali Meidenhad (EETS) 23 Man seith that eise maketh theof. 1387 J. TREVISA tr. Higden’s Polychronicon (1879) VII. 379 At the laste the bischop seide to hym, ‘Me thenke that opportunitie makethe a thefe’. 1623 W. CAMDEN Remains concerning Britain (ed. 3) 275 Opportunity makes the thief. 1670 J. RAY English Proverbs 129 Opportunity makes the thief. . . Therefore, masters . . ought to secure their moneys and goods under lock and key, that they do not give . . a temptation to steal. 1835 SOUTHEY Doctor III. cv. Opportunity, which makes thieves, makes lovers also. 1979 Daedalus Summer 107 A child steals from the sleeping woman’s pocket, acting out the proverb ‘Opportunity makes a thief.’ "honesty and dishonesty; opportunity, taken