The Book of Purification
1/166. Chapter:
The Junub Person Performing Wudu' When He Wants To Sleep
Sunan an-Nasai
أَخْبَرَنَا عُبَيْدُ اللَّهِ بْنُ سَعِيدٍ، قَالَ حَدَّثَنَا يَحْيَى، عَنْ عُبَيْدِ اللَّهِ، قَالَ أَخْبَرَنِي نَافِعٌ، عَنْ عَبْدِ اللَّهِ بْنِ عُمَرَ، أَنَّ عُمَرَ، قَالَ يَا رَسُولَ اللَّهِ أَيَنَامُ أَحَدُنَا وَهُوَ جُنُبٌ قَالَ " إِذَا تَوَضَّأَ " .
It was narrated from 'Abdullah bin 'Umar that 'Umar said: "O Messenger of Allah! May any one of us sleep while he is Junub?" He said: "When he performs Wudu'."
Reference : Sunan an-Nasa'i 259In-book reference : Book 1, Hadith 260English translation : Vol. 1, Book 1, Hadith 260