Mukhtasar Muslim

Sayyiduna Jabir (may Allah be pleased with him) says that two boys fought with each other. One of them was from the Muhajirun and the other from the Ansar. The Muhajir called his fellow Muhajirun and the Ansari called the Ansar, so the Messenger of Allah (peace and blessings be upon him) came out and said, "This is a call of ignorance (that each one seeks help from his own people and fights against the other group; in Islam, all Muslims are one)." The people said, "O Messenger of Allah! (It is not a big matter) two boys fought and one struck the other on the buttocks." The Prophet (peace and blessings be upon him) said, "There is nothing to fear (I thought it was a major disturbance). A person should help his brother whether he is an oppressor or oppressed. If he is an oppressor, then help him by stopping him from oppression, and if he is oppressed, then help him (and rescue him from the clutches of the oppressor)."