The Prophet ﷺ said, "The distance between the shoulders of the disbeliever in the Fire is a journey of three days for a swift rider."
عن النبي ﷺ قال: ما بين منكبي الكافر في النار مسيرة ثلاثة أيام للراكب المسرع.
Bukhari narrated it in the chapter on Riqaq (6551), and Muslim narrated it in the chapter on Paradise (2852), both through the route of Fudayl (he is Ibn Ghazwan), from Abu Hazim, from Abu Hurairah, and he related it. The wording given is Muslim's. Bukhari did not mention his statement, "in the Fire."