I heard the Messenger of Allah ﷺ say, "Fever wipes away sins just as a tree sheds its leaves."
سمعت رسول الله ﷺ يقول: إن الحمى تحط الخطايا كما تحط الشجر ورقها.
Ibn Abu Dunya narrated it in Marad wal-Kafarat (22) from Hashim bin Walid, who said, Abdul-Wahhab bin Ata narrated to us, from Umar bin Qays, from Abdul-Rahman bin Qasim, from his father, from Ayesha, and she related something similar.Its isnad is hasan, because of Abdul-Wahhab bin Ata, who is Khaffaf. He is disputed. Bukhari and Nasai declared him daif, while Ibn Main said, "There is no harm in him." Abu Hatim said, "His hadith is written down, his standing is that of truthfulness." Ibn Saad said, "He was truthful." Someone like him has his hadith graded hasan when he does not contradict others, which is why al-Hafiz said about him, "Truthful, perhaps he erred. They criticized a hadith of his about the merit of Abbas, it is said he committed tadlis regarding it from Thawr."As for his teacher Umar bin Qays, I was not able to identify him with certainty. He is either Umar bin Qays al-Masir bin Abu Muslim, the Kufan, Abu Sabbah, the client of Thaqif, who is trustworthy, and it is most likely that he is the one. Or he is Umar bin Qays al-Makki, Abu Jafar, known as Sindal, and the two are close in generation, except that the second is very daif. So whoever is certain that he is the second should strike out this hadith.