The line comes from Game of Thrones season 3, episode 9, The Rains of Castamere, which aired in 2013. At the Red Wedding, Roose Bolton speaks the words to Robb Stark moments before murdering him, signaling that House Lannister orchestrated the massacre. The phrase became shorthand for televised betrayal and spread through reaction videos, gaming montages and political memes. It endures because it condenses a shocking twist into one polite, menacing sentence that needs no explanation for fans.