The Messenger of Allah ﷺ said, "Fever, or the intensity of fever, comes from the blast of Hellfire, so cool it down with water."
حدثنا ابن نمير عن هشام عن أبيه
أن رسول الله ﷺ قال إن الحمى أو شدة الحمى من فيح جهنم فأبردوها بالماء
Its isnad is sahih, and it is like the one before it. (1) In the Halabi edition, "Abdullah told us, my father told me, Ibn Numayr told us, Yahya told us," with the addition of Ibn Numayr. This is an overlap from the line before it.