´Aishah narrated that:` The Messenger of Allah said: "The believer is not afflicted by the prick of a thorn or what is worse (or greater) than that, except that by it Allah raises him in rank and removes sin from him."
Hadith Referenceسنن ترمذي / كتاب الجنائز عن رسول الله صلى الله عليه وسلم / 965
´Abu Sa'eed Al-Khudri (may Allah be pleased with him) narrated that:` The Messenger of Allah said: "Nothing afflicts the believer, whether fatigue, grief, disease - even a worry that concerns him - except that by it, Allah removes something from his bad deeds."
Hadith Referenceسنن ترمذي / كتاب الجنائز عن رسول الله صلى الله عليه وسلم / 966