Sahih Muslim Book - 48, Hadith - 6892

وَحَدَّثَنَا إِسْحَاقُ بْنُ مُوسَى الأَنْصَارِىُّ حَدَّثَنَا أَنَسُ بْنُ عِيَاضٍ حَدَّثَنَا عُبَيْدُ اللَّهِ حَدَّثَنِى سَعِيدُ بْنُ أَبِى سَعِيدٍ الْمَقْبُرِىُّ عَنْ أَبِيهِ عَنْ أَبِى هُرَيْرَةَ أَنَّ رَسُولَ اللَّهِ -صلى الله عليه وسلم- قَالَ « إِذَا أَوَى أَحَدُكُمْ إِلَى فِرَاشِهِ فَلْيَأْخُذْ دَاخِلَةَ إِزَارِهِ فَلْيَنْفُضْ بِهَا فِرَاشَهُ وَلْيُسَمِّ اللَّهَ فَإِنَّهُ لاَ يَعْلَمُ مَا خَلَفَهُ بَعْدَهُ عَلَى فِرَاشِهِ فَإِذَا أَرَادَ أَنْ يَضْطَجِعَ فَلْيَضْطَجِعْ عَلَى شِقِّهِ الأَيْمَنِ وَلْيَقُلْ سُبْحَانَكَ اللَّهُمَّ رَبِّى بِكَ وَضَعْتُ جَنْبِى وَبِكَ أَرْفَعُهُ إِنْ أَمْسَكْتَ نَفْسِى فَاغْفِرْ لَهَا وَإِنْ أَرْسَلْتَهَا فَاحْفَظْهَا بِمَا تَحْفَظُ بِهِ عِبَادَكَ الصَّالِحِينَ ».

It was narrated from Abu Hurairah that the Messenger of Allah (s.a.w) said: "When one of you goes to his bed, let him take the edge of his Izar (lower garment) and dust off his bed with it, and let him say the Name of Allah, for he does not know what came onto it after he left it. Then when he wants to lie down, let him lie down on his right side and say: 'Subhanaka rabbi, bika wada'tu janbi, wa bika arfa'uhu, in amskta nafsi faghfirli wa in arsaltaha fahfazha bima tahfazu bihi 'ibadakas-salihin (Glory is to You my Lord, by Your Grace I lay myself down and by Your Grace I get up again. If You keep my soul, then forgive it and if You send it back, then protect it with that with which You protect Your believing slaves)."'