Anas reported that Allah's Messenger (ﷺ) established fraternity between Abu Ubaida b. Jarrah and Abu Talha.
It was said to Anas b. Malik
You must have heard this that Allah's Messenger (ﷺ) said: There is no alliance (hilf) of brotherhood in Islam. Anas said: Allah's Messenger (ﷺ) established the bond of fraternity between the Quraish and the Ansar in his home.
Anas reported Allah's Messenger (ﷺ) established fraternity between the Quraish and the Ansar in his house at Medina.
Jubair b. Mut'im reported Allah's Messenger (ﷺ) as saying
There is no alliance (hilf) in Islam but (the hilf) established in the pre-Islamic days (for good). Islam intensifies and strengthens it.