Sahih al-Bukhari 3608
Book 61: Virtues and Merits of the Prophet (pbuh) and his Companions · Narrated by Abu Huraira
Arabic
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 ".
English translation
Narrated Abu Huraira: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
Reference: Sahih al-Bukhari 3608, Book of Virtues and Merits of the Prophet (pbuh) and his Companions. English translation by Dr. Muhammad Muhsin Khan.