عَنْ عَبْدِ اللَّهِ بْنِ بُرَيْدَةَ عَنْ أَبِيهِ رَضِيَ اللَّهُ عَنْهُ قَالَ: سَمِعْتُ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ يَقُولُ: ((الْعَهْدُ الَّذِي بَيْنَنَا وَبَيْنَهُمُ الصَّلَاةُ، فَمَنْ تَرَكَهَا فَقَدْ كَفَرَ))
It is narrated from Sayyiduna Buraidah (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: The covenant between us and them is the prayer; whoever abandons it has surely committed disbelief.