(4) باب أَعِنْ أَخَاكَ ظَالِمًا أَوْ مَظْلُومًا
Narrated Anas bin Malik:
Allah's Messenger (ﷺ) said, "Help your brother, whether he is an oppressor or he is an oppressed one."
Reference: Sahih al-Bukhari 2443
In-book reference: Book 46, Hadith 4
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 3, Book 43, Hadith 623