Mukhtasar Muslim (Abridged) 1798 — Reward for any harm or calamity

It is narrated from Sayyiduna Abu Sa'id Khudri (may Allah be pleased with him) and Sayyiduna Abu Hurairah (may Allah be pleased with him) that they heard the Messenger of Allah (peace and blessings of Allah be upon him) say: Whenever a believer is afflicted with any hardship, pain, illness, or sorrow—even the worry that befalls him—his sins are erased because of it.