The Book of Purification and its Sunnah
1/99. Chapter:
Those who say that the sexually impure should not sleep until he performs ablution like his ablution for prayer
Sunan Ibn Majah
حَدَّثَنَا مُحَمَّدُ بْنُ رُمْحٍ الْمِصْرِيُّ، أَنْبَأَنَا اللَّيْثُ بْنُ سَعْدٍ، عَنِ الزُّهْرِيِّ، عَنْ أَبِي سَلَمَةَ، عَنْ عَائِشَةَ، قَالَتْ كَانَ رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ إِذَا أَرَادَ أَنْ يَنَامَ وَهُوَ جُنُبٌ تَوَضَّأَ وُضُوءَهُ لِلصَّلاَةِ .
It was narrated that 'Aishah said: "When the Messenger of Allah wanted to sleep and he was sexually impure, he would perform ablution as for prayer."
Reference : Sunan Ibn Majah 584In-book reference : Book 1, Hadith 318English translation : Vol. 1, Book 1, Hadith 584