The line comes from Marvel's Captain America films, first spoken by a scrawny Steve Rogers in Captain America: The First Avenger in 2011 as he refuses to stay down in a fight. It returns in later films including Captain America: Civil War and Avengers: Endgame, becoming his defining catchphrase. Online, the clip spread through movie edits, GIFs and meme videos about persistence, and fans still quote it whenever someone keeps going long after they should have stopped, turning a heroic moment into shorthand for stubborn endurance.