Sahih Muslim – Hadith No : 6747

Jabir b. Abdullah reported that two young men, one from the Muhajirin (emigrants) and the other one from the Angr (helpers) fell into dispute and the Muhajir called his fellow Muhajirin, and the Ansari (the helper) called the Ansar (for help). In the meanwhile, Allah’s Messenger (may peace be upon him) came there and said: What is this, the proclamation of the days of jahiliya (ignorance)? They said: Allah’s Messenger, there is nothing serious. The two young men fell into dispute and the one struck at the back of the other. Thereupon he (the Holy Prophet) said: Well, a person should help his brother whether he is an oppressor or an oppressed. If he is the oppressor he should prevent him from doing it, for that is his help; and if he is the oppressed he should be helped (against oppression).

Hadith In Arabic Text :

حدثنا أحمد بن عبد الله بن يونس، حدثنا زهير، حدثنا أبو الزبير، عن جابر، قال اقتتل غلامان غلام من المهاجرين وغلام من الأنصار فنادى المهاجر أو المهاجرون يا للمهاجرين ‏.‏ ونادى الأنصاري يا للأنصار ‏.‏ فخرج رسول الله صلى الله عليه وسلم فقال ‏”‏ ما هذا دعوى أهل الجاهلية ‏”‏ ‏.‏ قالوا لا يا رسول الله إلا أن غلامين اقتتلا فكسع أحدهما الآخر قال ‏”‏ فلا بأس ولينصر الرجل أخاه ظالما أو مظلوما إن كان ظالما فلينهه فإنه له نصر وإن كان مظلوما فلينصره ‏”‏ ‏.‏

Chapter : The Book of Virtue; Good Manners and Joining of the Ties of Relationship – كتاب البر والصلة والآداب