Jabir bin Abdullah reported,

Two boys came to blows, one from the Emigrants and the other from the Helpers. The Emigrant boy cried out, "Help, Emigrants!" and the Helper boy cried out, "Help, Helpers!"The Messenger of Allah ﷺ came out and said, "Is this a call of the Days of Ignorance?"They replied, "No, by Allah, it is only that two boys came to blows, one of them kicking the other from behind."He said, "There is no harm in that. Let a man support his brother, whether he is the wrongdoer or the wronged. If he is the wrongdoer, let him restrain him, for that is supporting him. And if he is wronged, let him come to his aid."

Ahmad 14467

Sahih

حدثنا يحيى بن آدم وأبو النضر قالا حدثنا زهير أخبرنا أبو الزبير حدثنا

جابر قال

اقتتل غلامان غلام من المهاجرين وغلام من الأنصار فقال المهاجري يا للمهاجرين وقال الأنصاري يا للأنصار فخرج رسول الله ﷺ فقال أدعوى الجاهلية فقالوا لا والله إلا أن غلامين كسع أحدهما الآخر فقال لا بأس لينصر الرجل أخاه ظالما أو مظلوما فإن كان ظالما فلينهه فإنه له نصرة وإن كان مظلوما فلينصره

أحمد 14467صحيح
Contents
Reference
Commentary
Ayat
Collection
Musnad Ahmad
Book
Jabir bin Abdullah
Numbering
Darussalam 14467
Ahmad 14467