Sahih al-Bukhari 3608
Sahih al-Bukhari · Book 61: Virtues and Merits of the Prophet (pbuh) and his Companions · The signs of Prophethood in Islam
Narrated Abu Huraira:
حَدَّثَنَا الْحَكَمُ بْنُ نَافِعٍ ، حَدَّثَنَا شُعَيْبٌ ، عَنِ الزُّهْرِيِّ ، قَالَ أَخْبَرَنِي أَبُو سَلَمَةَ ، أَنَّ أَبَا هُرَيْرَةَ ـ رضى الله عنه ـ قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " لاَ تَقُومُ السَّاعَةُ حَتَّى يَقْتَتِلَ فِئَتَانِ دَعْوَاهُمَا وَاحِدَةٌ " .
Allah's Messenger (ﷺ) said, "The Day of (Judgment) will not be established till there is a war between two groups whose claims (or religion) will be the same."