Sahih Bukhari

Narrated Ibn `Umar:That a man came to him (while two groups of Muslims were fighting) and said, ""O Abu `Abdur Rahman! Don't you hear what Allah has mentioned in His Book: 'And if two groups of believers fight against each other...' (49.9) So what prevents you from fighting as Allah has mentioned in His Book?""' Ibn `Umar said, ""O son of my brother! I would rather be blamed for not fighting because of this Verse than to be blamed because of another Verse where Allah says: 'And whoever kills a believer intentionally..."" (4.93) Then that man said, ""Allah says:-- 'And fight them until there is no more afflictions (worshipping other besides Allah) and the religion (i.e. worship) will be all for Allah (Alone)"" (8.39) Ibn `Umar said, ""We did this during the lifetime of Allah's Messenger (ﷺ) when the number of Muslims was small, and a man was put to trial because of his religion, the pagans would either kill or chain him; but when the Muslims increased (and Islam spread), there was no persecution."" When that man saw that Ibn `Umar did not agree to his proposal, he said, ""What is your opinion regarding `Ali and `Uthman?"" Ibn `Umar said, ""What is my opinion regarding `Ali and `Uthman? As for `Uthman, Allah forgave him and you disliked to forgive him, and `Ali is the cousin and son-in-law of Allah's Messenger (ﷺ) ."" Then he pointed out with his hand and said, ""And that is his daughter's (house) which you can see