This excerpt is taken from Sheikh Hafiz Mubashir Hussain Lahori's book Signs of the Day of Judgment in the Light of Authentic Hadiths.
Sign of the Day of Judgment: Battle of Siffin
وعن أبى هريرة رضى الله عنه قال قال رسول الله صلى الله عليه وسلم : لا تقوم الساعة حتى تقتتل فتان عظيمتان يكون بينهما مقتلة عظيمة ودعوهما واحدة
It is narrated from Hazrat Abu Huraira (may Allah be pleased with him) that the Prophet Muhammad (peace be upon him and his family) said: "The Day of Judgment will not come until two large groups of Muslims fight a great battle, while both groups will claim to be on the right side."
Reference: Bukhari: Book of Apostates' Repentance: Chapter on the Prophet's Saying 'The Hour will not be established until...': 6935 Muslim: 2888 Ahmad: 412/2 702 Dala'il al-Nubuwwah: 418/6
In one narration, it is mentioned that one of these two groups (a third party) will leave the religion, and that group will be killed by the group that is closer to the truth.
Reference: (Muslim: Book of Zakat: Chapter on the Mention of the Kharijites and their Characteristics: 1065
عن أبى بكرة رضى الله عنه قال بينا رسول الله صلى الله عليه وسلم ذات يوم يخطب إذ جاء الحسن بن على فصعد إلى المنبر فضمه النبى ومسح على رأسه وقال : إن ابني هذا سيد ولعل الله أن يصلح على يديه بين فئتين عظيمتين من المسلمين
Hazrat Abu Bakrah (may Allah be pleased with him) said that one day the Prophet Muhammad (peace be upon him and his family) was delivering a sermon when Hasan bin Ali (may Allah be pleased with both of them) came and began to climb the pulpit. The Prophet (peace be upon him and his family) pulled him towards himself, kissed him on the head, and said: "This son of mine is a leader. Surely Allah will reconcile two great groups of Muslims through his hands."
Reference: Bukhari: Book of Tribulations: Chapter on the Prophet's Saying to Hasan bin Ali that 'This is my son, a leader, and perhaps Allah will reconcile two groups of Muslims through him': 7109 Ahmad: 52/5 Abu Dawood: 13/1
Benefits:
Respected readers, from the brief accounts of the Battle of Jamal on the previous pages, you must have somewhat understood the reality of this battle—that due to the intrigues of the Sabians (the conspiratorial followers of Abdullah bin Saba, the Jew), the compulsion of Hazrat Ali (may Allah be pleased with him), and the misunderstandings of Hazrat Aisha (may Allah be pleased with her) and others, the Muslims suffered a great loss in the form of war and corpses. However, the mention of the Battle of Siffin added salt to the previous wounds and caused old wounds to become fresh. The law of nature was fixed that Muslims would suffer the torment of internal conflicts; therefore, Allah Almighty did not accept the Prophet Muhammad’s (peace be upon him and his family) prayer that Muslims should not fight among themselves (the reference has already passed). After the Battle of Jamal, Hazrat Ali (may Allah be pleased with him) and many wise people did not want to engage in another new war, but due to the strong intrigues of the Sabians and the fanaticism of people like Ashtar Nakha'i and Abu Amr Salmi, all efforts for reconciliation between Hazrat Ali (may Allah be pleased with him) and Amir Muawiyah (may Allah be pleased with him) failed, and a bloody battle took place at Siffin, in which thousands of people from both sides, most of whom were companions, were killed without exaggeration. Thus, the conspiracies of the hypocrites and divine destiny were at work. Before the start of the battle and the attempts at reconciliation, another issue arose, which can be called a tragedy without exaggeration: the people of Syria had accepted Muawiyah (may Allah be pleased with him) as their caliph in opposition to Hazrat Ali (may Allah be pleased with him). Gradually, the issue of the right to the caliphate had also firmly taken its place in the field along with the killing of Uthman. During this period, Hazrat Ali (may Allah be pleased with him) was martyred as a result of a conspiracy, and people appointed Hazrat Hasan (may Allah be pleased with both of them) as his successor (caliph). However, Hazrat Hasan (may Allah be pleased with him), fully fulfilling the prophecy of the Prophet Muhammad (peace be upon him and his family), with great wisdom, gave allegiance to Amir Muawiyah (may Allah be pleased with him) and renounced the caliphate. Thus, the Muslim Ummah once again gathered under the banner of Amir Muawiyah (may Allah be pleased with him) and became engaged in recognizing and pursuing its real enemies.
