Caution: Translations of Quran and Ḥadīth may lead to possible misapplications and misinterpretations. This site is intended for students of sacred knowledge that are proficient in comprehending classical Arabic and have a strong foundation in Islamic sciences. Also note that religious injunctions rely on several aspects beyond what one may glean through reading individual aḥādīth.
bayhaqi:597Abū al-Ḥasan ʿAlī b. Aḥmad b. ʿAbdān > Aḥmad b. ʿUbayd al-Ṣaffār > Muḥammad b. Shādhān al-Jawharī > Zakariyyā b. ʿAdī > ʿAbd al-Salām b. Ḥarb > Yazīd al-Dālānī > Qatādah > Abū al-ʿĀliyah > Ibn ʿAbbās

[Machine] "That the Messenger of Allah ﷺ slept in prostration until he snored and breathed heavily. I said, 'O Messenger of Allah, have you slept?' He replied, 'Indeed, it is obligatory to perform ablution for the one who lies down on his side, for when he lies down on his side, his joints loosen like this.'"  

البيهقي:٥٩٧أَخْبَرَنَا أَبُو الْحَسَنِ عَلِيُّ بْنُ أَحْمَدَ بْنِ عَبْدَانَ نا أَحْمَدُ بْنُ عُبَيْدٍ الصَّفَّارُ نا مُحَمَّدُ بْنُ شَاذَانَ الْجَوْهَرِيُّ نا زَكَرِيَّا بْنُ عَدِيٍّ نا عَبْدُ السَّلَامِ بْنُ حَرْبٍ عَنْ يَزِيدَ الدَّالَانِيِّ عَنْ قَتَادَةَ عَنْ أَبِي الْعَالِيَةِ عَنِ ابْنِ عَبَّاسٍ

أَنَّ رَسُولَ اللهِ ﷺ نَامَ فِي سُجُودِهِ حَتَّى غَطَّ وَنَفَخَ قُلْتُ يَا رَسُولَ اللهِ قَدْ نِمْتَ؟ فَقَالَ إِنَّمَا يَجِبُ الْوُضُوءُ عَلَى مَنْ وَضَعَ جَنْبَهُ فَإِنَّهُ إِذَا وَضَعَ جَنْبَهُ اسْتَرْخَتْ مَفَاصِلُهُ هَكَذَا  

رَوَاهُ جَمَاعَةٌ عَنْ عَبْدِ السَّلَامِ بْنِ حَرْبٍ وَقَالَ بَعْضُهُمْ فِي الْحَدِيثِ إِنَّمَا الْوضُوءُ عَلَى مَنْ نَامَ مُضْطَجِعًا فَإِنَّهُ إِذَا اضْطَجَعَ اسْتَرْخَتْ مَفَاصِلُهُ