Bukhari

Hadith Commentary:
Both parties will claim that they are Muslims and are fighting for the truth, even though in reality one will be upon the truth and the other upon falsehood. This prophecy was made by the Prophet sallallahu alayhi wa sallam regarding the battle that took place between Ali radi Allahu anhu and Muawiyah radi Allahu anhu.
Both sides were Muslims and claimed to be fighting for the truth.
And it is itself narrated from Ali radi Allahu anhu that he said regarding Muawiyah radi Allahu anhu and his group that they are our brothers who have rebelled against us; they are neither disbelievers nor sinners (Wahidi).
There is a lesson in these events for today’s so-called scholars as well, who, over the slightest matters, begin hurling accusations of disbelief and sin at each other.
In this way, they scatter the unity of the Ummah.
May Allah, the Exalted, grant such claimants of knowledge understanding and insight so that they recognize the temperament of the times and strive to gather the unity of the Ummah. If this is not done, then the time is coming when, along with the destruction of the Ummah, such so-called leaders of the Ummah will also be consigned to oblivion, and the sin of the Ummah’s ruin will be upon their heads.
Today, on 22 Shawwal 1391 AH, this note was recorded in Masjid Ahl-e-Hadith, Harlapur, Harihar.
Rabbana taqabbal minna innaka anta as-sami’ul aleem.
Ameen.

Hadith Commentary:
➊ Each of the two groups will claim that they are upon the truth and that the other party is not upon the truth, but in reality, only one group will be upon the truth. However, the other group will be excused due to an ijtihadi (independent juristic reasoning) error, because the battle between the two groups will be based on ijtihad, and the leader of each group will be a mujtahid (qualified jurist). When a mujtahid makes a mistake in his ruling, he is not sinful.

➋ In this hadith, the Messenger of Allah (sallallahu alayhi wa sallam) gave news of the unseen, and it happened exactly as he said. Thus, at the place of Siffin, there was a battle between Ali (radi Allahu anhu) and Muawiyah (radi Allahu anhu). Both claimed that they were upon the truth, but in reality, after the martyrdom of Uthman (radi Allahu anhu), all the people of authority and decision pledged allegiance to Ali (radi Allahu anhu), and he alone was the Khalifah of the Muslims and was upon the truth in presenting his claim. Only the people of Syria were against pledging allegiance to him. And Allah knows best.