The Hanafi scholar Abu Bakr al-Jassas said: “His Madhab [i.e., Abu Hanifa] was well-known for fighting oppressors and imams of injustice. Therefore, Al-Awza’i said: We tolerated Abu Hanifa for everything until he came to us with the sword - meaning fighting the oppressors - but we did not tolerate him for that. And among his words were: The obligation to enjoin good and forbid evil is obligatory by word, and if it is not commanded to do so, then by the sword, according to what was narrated from the Prophet. Ibrahim al-Sayegh - who was one of the jurists of the people of Khurasan and who narrated their news and ascetics - asked him about enjoining good and forbidding evil, and he said: It is obligatory, and he narrated to him with a hadith on the authority of Ikrimah on the authority of Ibn Abbas that The Prophet, صلي الله عليه وسلم said, “The best of the martyrs is Hamzah bin Abdul Muttalib and a man who rose up to an unjust imam and enjoined upon him what is right and forbade him from what is evil, so he was killed.”.
Source: Ahkam Al Quran 1/86-87
Source: Ahkam Al Quran 1/86-87