Sunan an-Nasa'i 615
سنن النسائي#615Sahihأَخْبَرَنَا قُتَيْبَةُ، قَالَ حَدَّثَنَا حَمَّادُ بْنُ زَيْدٍ، عَنْ ثَابِتٍ، عَنْ عَبْدِ اللَّهِ بْنِ رَبَاحٍ، عَنْ أَبِي قَتَادَةَ، قَالَ ذَكَرُوا لِلنَّبِيِّ صلى الله عليه وسلم نَوْمَهُمْ عَنِ الصَّلاَةِ فَقَالَ " إِنَّهُ لَيْسَ فِي النَّوْمِ تَفْرِيطٌ إِنَّمَا التَّفْرِيطُ فِي الْيَقَظَةِ فَإِذَا نَسِيَ أَحَدُكُمْ صَلاَةً أَوْ نَامَ عَنْهَا فَلْيُصَلِّهَا إِذَا ذَكَرَهَا " .
It was narrated that Abu Qatadah said:"They told the Prophet (ﷺ) that they had slept and missed the prayer. He said: 'There is no negligence when one sleeps, rather negligence is when one is awake. If any one of you forgets a prayer or sleeps and misses it, let him pray it when he remembers it
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: 6:122