Musnad Ahmad 10:1

Bishr ibn al-Mufaddal narrated to us, from Abd al-Rahman ibn Ishaq, from al-Zuhri, from Muhammad ibn Jubayr ibn Mut'im, from his father, from Abd al-Rahman ibn Awf, from the Prophet, peace and blessings of Allah be upon him, who said: "I witnessed the alliance of the Mutayyibin (the Scented Ones) with my paternal uncles while I was a boy, and I would not love to have red camels in exchange for breaking it." Al-Zuhri said: The Messenger of Allah, peace and blessings of Allah be upon him, said: "Islam did not encounter an alliance except that it increased it in strength, and there is no alliance in Islam." And the Messenger of Allah, peace and blessings of Allah be upon him, brought together the Quraysh and the Ansar.