Sayyiduna Abu al-Darda' (may Allah be pleased with him) narrates: I heard the Prophet (peace and blessings be upon him) say: "Headache and fever keep afflicting the believer, and the believer's sins are like Mount Uhud; then when that illness leaves the believer, not even the weight of a mustard seed of sin remains on him."
Ahmad and al-Tabarani recorded it in al-Mu'jam al-Kabir and al-Mu'jam al-Awsat. Its chain contains a narrator, Ibn Lahi'ah, about whom there is criticism.
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الجنائز / 3796