(phrases and proverbs).
At swords' point. In deadly hostility, ready to fight each other with swords. Poke not fire with a sword. This was a precept of Pythagoras, meaning add not fuel to fire, or do not irritate an angry man by sharp words which will only increase his rage. (See Iamblichus Protreptics, symbol ix.)
To put to the sword. To slay.
Your tongue is a double-edged sword. You first say one thing and then the contrary; your argument cuts both ways. The allusion is to the double-edged sword out of the mouth of the Son of Man- one edge to condemn, and the other to save. (Rev. i. 16.)
Yours is a Delphic sword- it cuts both ways. Erasmus says a Delphic sword is that which accommodates itself to the pro or con. of a subject. The reference is to the double meanings of the Delphic oracles, called in Greek Delphike muchaira.
Sword and Cloak Plays So Calderon called topical or modern comedies, because the actors wore cloaks and swords (worn by gentlemen of the period) instead of heraldic, antique, or dramatico-historic dresses, worn in tragedy
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894