Hadith 616

It was narrated that Abu Qatadah said: "The Messenger of Allah (PBUH) said: 'There is no negligence when one sleeps, rather negligence is when one does not offer one prayer until the time of the next prayer comes and he realizes that he has missed a prayer.'"

أَخْبَرَنَا سُوَيْدُ بْنُ نَصْرٍ، قَالَ أَنْبَأَنَا عَبْدُ اللَّهِ، - وَهُوَ ابْنُ الْمُبَارَكِ - عَنْ سُلَيْمَانَ بْنِ الْمُغِيرَةِ، عَنْ ثَابِتٍ، عَنْ عَبْدِ اللَّهِ بْنِ رَبَاحٍ، عَنْ أَبِي قَتَادَةَ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏"‏ لَيْسَ فِي النَّوْمِ تَفْرِيطٌ إِنَّمَا التَّفْرِيطُ فِيمَنْ لَمْ يُصَلِّ الصَّلاَةَ حَتَّى يَجِيءَ وَقْتُ الصَّلاَةِ الأُخْرَى حِينَ يَنْتَبِهُ لَهَا ‏"‏ ‏.‏

Reference: 1106200
In-book reference: Book 6, Hadith 616
Hadith 616 - The Book of the Times (of Prayer) - Sunan an-Nasa'i - Sunnah.com