Musnad Abu Ya'la al-Mawsili 246:16

Zuhayr narrated to us, Ishaq bin Yusuf narrated to us, Zakariya narrated to us, from Sa'd bin Ibrahim, from Nafi' bin Jubayr, from his father, that the Prophet (peace be upon him) said: "There is no alliance (hilf) in Islam. And whatever alliance existed in the Pre-Islamic period (Jahiliyyah), Islam has only increased it in firmness."