أَخْبَرَنَا الْحُسَيْنُ بْنُ حُرَيْثٍ، قَالَ أَنْبَأَنَا الْفَضْلُ بْنُ مُوسَى، عَنِ الْحُسَيْنِ بْنِ وَاقِدٍ، عَنْ عَبْدِ اللَّهِ بْنِ بُرَيْدَةَ، عَنْ أَبِيهِ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " إِنَّ الْعَهْدَ الَّذِي بَيْنَنَا وَبَيْنَهُمُ الصَّلاَةُ فَمَنْ تَرَكَهَا فَقَدْ كَفَرَ " .
It was narrated from 'Abdullah bin Buraidah that his father said: "The Messenger of Allah (PBUH) said: 'The covenant that stands between us and them is the Salah; whoever abandons it, he has committed disbelief.'" Translation Not Available
Book Ref: Sunan An Nisai Book 5 Hadith 463
Web Ref: Sunan An Nisai Vol 1 Book 5 Hadith 464