Woken by something he had been shown
Umm Salama heard him get up in the night saying it.
سُبْحَانَ اللَّهِ، مَاذَا أُنْزِلَ مِنَ الْخَزَائِنِ وَمَاذَا أُنْزِلَ مِنَ الْفِتَنِ
Glory be to Allah. What treasures have been sent down tonight, and what tribulations have been sent down. Who will wake the occupants of these rooms to pray? Many a clothed woman in this world will be naked in the Hereafter.
The full narration
Um Salama said:The Prophet (ﷺ) woke up and said, "Glorified be Allah: What great (how many) treasures have been sent down, and what great (how many ) afflictions have been sent down
Source
Ṣaḥīḥ al-Bukhārī · 3599
Ṣaḥīḥ
- Agreed upon as authentic (al-Bukhārī / Muslim)