Kitāb al-Muʾmin

Hadith 30
trials-afflictionstaqwa
30 - عن محمد بن مسلم قال: سمعت أبا عبد الله (ع) يقول المؤمنُ لا يمضي عليه أربعون ليلةً إلاّ عُرض له أمرٌ يحزِنه، ويُذكّره به.
30. It has been narrated that Muhammad ibn Muslim said: I heard Abu 'Abd Allah (a.s) saying: No forty nights pass for a believer except a matter befalls him that grieves him and reminds him (of Allah).
Source: Ḥusayn b. Saʿīd al-Ahwāzī