Sunan an-Nasa'i 1
سنن النسائي#1Sahihأَخْبَرَنَا 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 " .
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
Scholarly Authentication
The label above is the grade most of these scholars gave — one dissenting opinion no longer speaks for all of them. If any scholar calls a narration fabricated, that verdict is shown instead, whatever the others say. Each scholar's own wording:
In-book reference: 1:1