Sunan an-Nasa'i 1607
سنن النسائي#1607Sahihأَخْبَرَنَا مُحَمَّدُ بْنُ عَبْدِ اللَّهِ بْنِ يَزِيدَ، قَالَ حَدَّثَنَا سُفْيَانُ، عَنْ أَبِي الزِّنَادِ، عَنِ الأَعْرَجِ، عَنْ أَبِي هُرَيْرَةَ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " إِذَا نَامَ أَحَدُكُمْ عَقَدَ الشَّيْطَانُ عَلَى رَأْسِهِ ثَلاَثَ عُقَدٍ يَضْرِبُ عَلَى كُلِّ عُقْدَةٍ لَيْلاً طَوِيلاً أَىِ ارْقُدْ فَإِنِ اسْتَيْقَظَ فَذَكَرَ اللَّهَ انْحَلَّتْ عُقْدَةٌ فَإِنْ تَوَضَّأَ انْحَلَّتْ عُقْدَةٌ أُخْرَى فَإِنْ صَلَّى انْحَلَّتِ الْعُقَدُ كُلُّهَا فَيُصْبِحُ طَيِّبَ النَّفْسِ نَشِيطًا وَإِلاَّ أَصْبَحَ خَبِيثَ النَّفْسِ كَسْلاَنَ " .
It was narrated that Abu Hurairah said:The Messenger of Allah (ﷺ) said: 'When any one of you goes to sleep, the Shaitan ties three knots on his head, saying each time: "(Sleep) a long night." If he wakes up and remembers Allah (SWT), one knot is undone. If he performs wudu', another knot is undone. If he prays, all the knots are undone and he starts his day in a good mood and feeling energetic. Otherwise he starts his day in a bad mood and feeling lethargic
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: 20:10