(50) باب مُؤَاخَاةِ النَّبِيِّ صلى الله عليه وسلم بَيْنَ أَصْحَابِهِ رضى الله تعالى عنهم
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.
Reference: Sahih Muslim 2530
In-book reference: Book 44, Hadith 294
USC-MSA web (English) reference(deprecated numbering scheme): Book 31, Hadith 6146