Sahih al-Bukhari Book 61, Hadith 115
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."
My companions learned (something about) good (through asking the Prophet) while I learned (something about) evil.
The Prophet (ﷺ) said, "The Hour will not be established till there is a war between two groups among whom there will be a great number of casualties, though the claims (or religion) of both of them will be one and the same. And the Hour will not be established till there appear about thirty liars, all of whom will be claiming to be the messengers of Allah. "