Sunan an-Nasa'i, Volume 1, Book 6, Hadith 616 (DarusSalam) ⓘ

It was narrated that Abu Qatadah said: "They told the Prophet 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.'"

أَخْبَرَنَا 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 ‏" ‏ ‏.‏