The Messenger of Allah ﷺ visited an Arabi who was suffering from a fever, to check on him. He said, "It is an expiation and a purification."The Arabi replied, "Rather, it is a raging fever upon an old man, driving him to the grave."So the Messenger of Allah ﷺ stood up and left him.
أن رسول الله ﷺ دخل على أعرابي يعوده، وهو محموم فقال: كفارة وطهور فقال الأعرابي: بل حمى تفور على شيخ كبير، تزيره القبور. فقام رسول الله ﷺ وتركه.
Ahmad (13616) narrated it from Affan, who said, Hammad bin Salama narrated to us, Abu Rabia narrated to us, from Anas, and he related it. Its isnad is hasan because of Abu Rabia, who is Sinan bin Rabia Bahili, concerning whom there is disagreement, but his hadith is hasan, especially when supported by corroborating narrations.