عَنْ عَبْدِ اللَّهِ رَضِيَ اللَّهُ عَنْهُ عَنِ النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ أَنَّهُ كَانَ إِذَا نَامَ وَضَعَ يَمِينَهُ تَحْتَ خَدِّهِ وَقَالَ اللَّهُمَّ قِنِي عَذَابَكَ يَوْمَ تَجْمَعُ عِبَادَكَ
It is narrated from Sayyiduna Abdullah (may Allah be pleased with him) that when the Noble Prophet (peace and blessings be upon him) would go to sleep, he would place his right hand under his right cheek and recite this supplication: "Allahumma qini ‘adhabaka yawma tajma‘u ‘ibadaka" (O Allah! On the day You gather Your servants, save me from Your punishment).