عَنْ عَائِشَةَ رَضِيَ اللَّهُ عَنْهَا قَالَتْ: كَانَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ إِذَا كَانَ جُنُبًا وَأَرَادَ أَنْ يَنَامَ وَهُوَ جُنُبٌ تَوَضَّأَ وَضُوءَهُ لِلصَّلَاةِ قَبْلَ أَنْ يَنَامَ وَكَانَ يَقُولُ: ((مَنْ أَرَادَ أَنْ يَنَامَ وَهُوَ جُنُبٌ فَلْيَتَوَضَّأْ وَضُوءَهُ لِلصَّلَاةِ))
It is narrated from Sayyida Aisha (may Allah be pleased with her), she says: When the Messenger of Allah (peace and blessings be upon him) would become junub and intended to sleep, he (peace and blessings be upon him) would perform ablution as for prayer before sleeping and would say: Whoever intends to sleep in a state of janabah should perform ablution as for prayer.