I pray thee, good Mercutio, let’s retire:
The day is hot, the Capulets abroad,
And, if we meet, we shall not scape a brawl;
For now, these hot days, is the mad blood stirring.

– William Shakespeare

Romeo and Juliet, Act 3, Scene 1. In the scene’s opening lines Benvolio tries to persuade Mercutio to go home with him in order to avoid running into the Capulets. If they meet a brawl is inevitable, he predicts – correctly, as it turns out. He uses the metaphor of "mad blood stirring" during the hot weather, to suggest the escalating tensions between the rival Capulets and Montagues. Benvolio’s words foreshadow the fights between Mercutio and Tybalt, and Romeo and Tybalt, resulting in the deaths of Tybalt and Mercutio.