Есть места, где спросить такие вещи. http://phrases.shu.ac.uk/bulletin_board/7/messages/132.html

Надеюсь, ссылка сработает. На всякий случай копирую основную информацию. Shakespeare, 'The Merry Wives of Windsor' (1600).'Falstaff: I will not lend thee a penny. Pistol: Why, then, the world's mine oyster, Which I with sword will open.' Act II, Scene II." If you boast that 'The world's my oyster' nowadays, you are claiming that the world's riches are yours to leisurely pluck from the shell. The braggart ensign Pistol, however, utters the phrase as sort of a threat -- of the aggressively bombastic kind he's known for. Sir John Falstaff, a baggart almost the equal of Pistol, refuses to lend him a penny; Pistol promises to use his sword, if not on Falstaff, then on other helpless victims, to pry open their purses. Pistol's thievish intentions have largely been forgotten, and 'The world's my oyster' has become merely a conceited proclamation of opportunity."