Messenger of Allah 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."  

قَالَ رَسُولُ اللَّهِ ﷺ لاَ تَقُومُ السَّاعَةُ حَتَّى يَقْتَتِلَ فِئَتَانِ دَعْوَاهُمَا وَاحِدَةٌ  

The last Hour will not come until the two parties (of Muslims) confront each other and there is a large-scale massacre amongst them and the claim of both of them is the same.  

عَنْ رَسُولِ اللَّهِ ﷺ فَذَكَرَ أَحَادِيثَ مِنْهَا وَقَالَ رَسُولُ اللَّهِ ﷺ لاَ تَقُومُ السَّاعَةُ حَتَّى تَقْتَتِلَ فِئَتَانِ عَظِيمَتَانِ وَتَكُونُ بَيْنَهُمَا مَقْتَلَةٌ عَظِيمَةٌ وَدَعْوَاهُمَا وَاحِدَةٌ  

Messenger of Allah ﷺ said, "The Hour will not be established (1) till two big groups fight each other whereupon there will be a great number of casualties on both sides and they will be following one and the same religious doctrine, (2) till about thirty Dajjals (liars) appear, and each one of them will claim that he is Messenger of Allah ﷺ, (3) till the religious knowledge is taken away (by the death of Religious scholars) (4) earthquakes will increase in number (5) time will pass quickly, (6) afflictions will appear, (7) Al-Harj, (i.e., killing) will increase, (8) till wealth will be in abundance ---- so abundant that a wealthy person will worry lest nobody should accept his Zakat, and whenever he will present it to someone, that person (to whom it will be offered) will say, 'I am not in need of it, (9) till the people compete with one another in constructing high buildings, (10) till a man when passing by a grave of someone will say, 'Would that I were in his place (11) and till the sun rises from the West. So when the sun will rise and the people will see it (rising from the West) they will all believe (embrace Islam) but that will be the time when: (As Allah said,) 'No good will it do to a soul to believe then, if it believed not before, nor earned good (by deeds of righteousness) through its Faith.' (6.158) And the Hour will be established while two men spreading a garment in front of them but they will not be able to sell it, nor fold it up; and the Hour will be established when a man has milked his she-camel and has taken away the milk but he will not be able to drink it; and the Hour will be established before a man repairing a tank (for his livestock) is able to water (his animals) in it; and the Hour will be established when a person has raised a morsel (of food) to his mouth but will not be able to eat it." (Using translation from Bukhārī 7121)  

وَقَالَ رَسُولُ اللهِ ﷺ لَا تَقُومُ السَّاعَةُ حَتَّى تَقْتَتِلَ فِئَتَانِ عَظِيمَتَانِ يَكُونُ بَيْنَهُمَا مَقْتَلَةٌ عَظِيمَةٌ وَدَعْوَاهُمَا وَاحِدَةٌ  

The last Hour will not come until the two parties (of Muslims) confront each other and there is a large-scale massacre amongst them and the claim of both of them is the same. (Using translation from Muslim 157i)   

قَالَ رَسُولُ اللهِ ﷺ لَا تَقُومُ السَّاعَةُ حَتَّى تَقْتَتِلَ فِئَتَانِ عَظِيمَتَانِ تَكُونُ بَيْنَهُمَا مَقْتَلَةٌ عَظِيمَةٌ وَدَعْوَاهُمَا وَاحِدَةٌ  

The last Hour will not come until the two parties (of Muslims) confront each other and there is a large-scale massacre amongst them and the claim of both of them is the same. (Using translation from Muslim 157i)   

وَقَالَ رَسُولُ اللَّهِ ﷺ «لَا تَقُومُ السَّاعَةُ حَتَّى تَقْتَتِلَ فِئَتَانِ عَظِيمَتَانِ بَيْنَهُمَا مَقْتَلَةٌ عَظِيمَةٌ دَعْوَاهُمَا وَاحِدَةٌ»