عَنْ أَبِيهِ عَنْ أَبِي هُرَيْرَةَ رَضِيَ اللَّهُ عَنْهُ قَالَ قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ إِذَا أَتَى أَحَدُكُمْ فِرَاشَهُ فَلْيَنْزِعْ دَاخِلَةَ إِزَارِهِ ثُمَّ لِيَنْفُضْ بِهَا فِرَاشَهُ فَإِنَّهُ لَا يَدْرِي مَا حَدَثَ عَلَيْهِ بَعْدَهُ ثُمَّ لِيَضْطَجِعْ عَلَى جَنْبِهِ الْأَيْمَنِ ثُمَّ لِيَقُلْ بِاسْمِكَ رَبِّي وَضَعْتُ جَنْبِي وَبِكَ أَرْفَعُهُ إِنْ أَمْسَكْتَ نَفْسِي فَارْحَمْهَا وَإِنْ أَرْسَلْتَهَا فَاحْفَظْهَا بِمَا حَفِظْتَ بِهِ عِبَادَكَ الصَّالِحِينَ
It is narrated from Sayyiduna Abu Hurairah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: When a person comes to his bed, he should take the edge of his lower garment and use it to dust off his bed, for he does not know what has happened after him. Then he should lie down on his right side and recite this supplication: "BISMIKA RABBI WADA'TU JANBI, IN AMSAKTA NAFSI FARHAMHA, WA IN ARSALTAHA FAHFADHA BIMA HAFIDHTA BIHI 'IBADAKA AS-SALIHIN." (O my Lord! In Your name I have laid down my side. If You take my soul, then have mercy on it, and if You release it, then protect it as You protect Your righteous servants.)