(17) باب الأَمْرِ وَالنَّهْىِ
Narrated AbuSa'id al-Khudri:
The Prophet (ﷺ) said: The best fighting (jihad) in the path of Allah is (to speak) a word of justice to an oppressive ruler. (ID)
Reference (ID): Sunan Abi Dawud 4344 (ID)
In-book reference (ID): Book 39, Hadith 54 (ID)
English translation (ID): Book 38, Hadith 4330 (ID)