عَنْ حَفْصَةَ ابْنَةِ عُمَرَ زَوْجِ النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ قَالَتْ كَانَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ إِذَا آوَى إِلَى فِرَاشِهِ وَضَعَ يَدَهُ الْيُمْنَى تَحْتَ خَدِّهِ وَقَالَ ”رَبِّ قِنِي عَذَابَكَ يَوْمَ تَبْعَثُ عِبَادَكَ“ ثَلَاثًا
It is narrated from Sayyidah Hafsah (may Allah be pleased with her) that when the Messenger of Allah (peace and blessings be upon him) would come to his bed, he would place his right hand under his right cheek and recite this supplication three times: "Rabbī qinī ‘adhābaka yawma tab‘athu ‘ibādak" (O my Lord! Protect me from Your punishment on the day You resurrect Your servants).