Sahih al-Bukhari Book 46, Hadith 4
Allah's Messenger (ﷺ) said, "Help your brother, whether he is an oppressor or he is an oppressed one."
Allah's Messenger (ﷺ) said, "A Muslim is a brother of another Muslim, so he should not oppress him, nor should he hand him over to an oppressor. Whoever fulfilled the needs of his brother, Allah will fulfill his needs; whoever brought his (Muslim) brother out of a discomfort, Allah will bring him out of the discomforts of the Day of Resurrection, and whoever screened a Muslim, Allah will screen him on the Day of Resurrection . "
Allah's Messenger (ﷺ) said, "Help your brother, whether he is an oppressor or he is an oppressed one. People asked, "O Allah's Messenger (ﷺ)! It is all right to help him if he is oppressed, but how should we help him if he is an oppressor?" The Prophet (ﷺ) said, "By preventing him from oppressing others."