The Prophet ﷺ said, "A man may utter a word, never imagining it could reach where it does, and because of it he plunges into the Fire for a distance of seventy autumns."
حدثنا عبد الرحمن يعني ابن مهدي حدثنا جرير بن حازم قال سمعت الحسن يحدث
عن النبي ﷺ قال إن الرجل ليتكلم بالكلمة وما يرى أنها تبلغ حيث بلغت يهوي بها في النار سبعين خريفا
Its chain of transmission is sahih. Tirmidhi related it, 4/557, no. 2314, in the Book of Zuhd, regarding one who speaks a word that makes people laugh, and he said it is hasan gharib. Ibn Majah also related it, 2/1313, no. 3970, as did Malik, 2/985.