You must have heard this that Messenger of Allah ﷺ said: There is no alliance (hilf) of brotherhood in Islam. Anas said: Messenger of Allah ﷺ established the bond of fraternity between the Quraish and the Ansar in his home.
أَنَّ رَسُولَ اللَّهِ ﷺ قَالَ لاَ حِلْفَ فِي الإِسْلاَمِ فَقَالَ أَنَسٌ قَدْ حَالَفَ رَسُولُ اللَّهِ ﷺ بَيْنَ قُرَيْشٍ وَالأَنْصَارِ فِي دَارِهِ