كتاب الطهارة
1  
The Book of Purification
(1)
Chapter: Interpreting The Saying Of Allah, The Mighty And Sublime: When You Intend To Offer Salah (The Prayer), wash your faces and your hands (forearms) up to your elbows
(1)
Sunan an-Nasa'i 1
It was narrated from Abu Hurairah that the Prophet (ﷺ) said:
"When any one of you wakes from sleep, let him not dip his hand in (the water he uses for) his Wudu' until he has washed it three times, for none of you knows where his hand spent the night."
أَخْبَرَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، قَالَ حَدَّثَنَا سُفْيَانُ، عَنِ الزُّهْرِيِّ، عَنْ أَبِي سَلَمَةَ، عَنْ أَبِي هُرَيْرَةَ، أَنَّ النَّبِيَّ صلى الله عليه وسلم قَالَ ‏ "‏ إِذَا اسْتَيْقَظَ أَحَدُكُمْ مِنْ نَوْمِهِ فَلاَ يَغْمِسْ يَدَهُ فِي وَضُوئِهِ حَتَّى يَغْسِلَهَا ثَلاَثًا فَإِنَّ أَحَدَكُمْ لاَ يَدْرِي أَيْنَ بَاتَتْ يَدُهُ ‏"‏ ‏.‏
Grade: Sahih (Darussalam)
Reference : Sunan an-Nasa'i 1
In-book reference : Book 1, Hadith 1
English translation : Vol. 1, Book 1, Hadith 1