The Hallelujah chorus comes from Handel's Messiah, first performed in 1742, where a full choir repeats the word in rising celebration at the end of Part II. For centuries it has signalled triumph and religious joy in concerts, films and adverts. Online, editors borrowed that grand feeling for memes, using the swell to mock-celebrate tiny wins, lucky moments and dramatic reveals. Its recognisable melody and instant lift keep it useful long after the original oratorio context, especially for short comedy edits.