The line comes from a Covid era press conference by Netherlands prime minister Mark Rutte, when he addressed people ignoring restrictions and, in widely reported coverage of football supporters singing in stadiums, told them in Dutch to simply keep their mouths shut. The unusually blunt wording for a head of government was clipped, quoted in Dutch news and shared widely on social media. It has since become a reusable Dutch meme sound, detached from the original policy debate and used whenever someone needs a firm be quiet moment.