حَدَّثَنَا عَلِيُّ بْنُ مُحَمَّدٍ، حَدَّثَنَا وَكِيعٌ، عَنْ إِسْرَائِيلَ، عَنْ أَبِي إِسْحَاقَ، عَنْ أَبِي عُبَيْدَةَ، عَنْ عَبْدِ اللَّهِ، أَنَّ النَّبِيَّ ـ صلى الله عليه وسلم ـ كَانَ إِذَا أَوَى إِلَى فِرَاشِهِ وَضَعَ يَدَهُ - يَعْنِي الْيُمْنَى - تَحْتَ خَدِّهِ ثُمَّ قَالَ ‏"‏ اللَّهُمَّ قِنِي عَذَابَكَ يَوْمَ تَبْعَثُ - أَوْ تَجْمَعُ - عِبَادَكَ ‏"‏ ‏.‏

It was narrated from 'Abdullah that: whenever the Prophet (saas) went to his bed, he would put his hand - meaning his right hand - beneath his cheek then say: "Allahumma qini 'adhabaka yawm tab'athu - [or: tajma'u] - 'ibadaka (O Allah, save me from Your punishment on the Day when You resurrect - or gather - Your slaves)." Translation Not Available

Book Ref: Sunan Ibn Majah Book 34 Hadith 3877
Web Ref:  Sunan Ibn Majah Vol 5 Book 34 Hadith 3877