The Messenger of Allah ﷺ said, "Before the Hour there will be tribulations like patches of dark night. A man will be a believer in the morning and a disbeliever by evening, and a believer in the evening and a disbeliever by morning..." The hadith continues.
قال رسول الله ﷺ: إن بين يدي الساعة فتنا كقطع الليل المظلم، يصبح الرجل فيها مؤمنا ويمسي كافرا، ويمسي مؤمنا ويصبح كافرا… الحديث.
Abu Dawud (4259), Tirmidhi (2204), Ibn Majah (3961), and Ahmad (19730) all narrated it, and Ibn Hibban (5962) graded it sahih, all of them through Muhammad bin Jahada, from Abdul-Rahman bin Tharwan, from Huzayll bin Shurahbil, from Abu Musa, and he related it.Tirmidhi mentioned it in abridged form and said, "This is a hasan gharib hadith." And it is as he said, for Abdul-Rahman bin Tharwan's hadith is hasan. The discussion of this is set out at length in the collections on trials and great battles.