The Prophet ﷺ said the following day, the Day of Sacrifice, while he was at Mina, "Tomorrow we shall camp at the valley of Banu Kinanah, where they swore an oath upon disbelief." By this he meant al-Muhassab. That was because Quraysh and Kinanah had made a pact against Banu Hashim and Banu Abdul-Muttalib, or Banu Muttalib, that they would not intermarry with them nor trade with them until they handed over the Prophet ﷺ to them.
قال النبي ﷺ من الغد يوم النحر وهو بمنى نحن نازلون غدا بخيف بني كنانة حيث تقاسموا على الكفر. يعني بذلك المحصب. وذلك أن قريشا وكنانة، تحالفت على بني هاشم وبني عبد المطلب أو بني المطلب أن لا يناكحوهم، ولا يبايعوهم حتى يسلموا إليهم النبي ﷺ.
Bukhari narrated it in the Hajj chapter (1590) and Muslim in the Hajj chapter (1314), both from the hadith of Walid bin Muslim, who said, Uzai told me, Zuhri told me, Abu Salama told me, Abu Hurairah told us, and he related it.Ibn Ishaq said, "When Quraysh saw that the companions of the Messenger of Allah had settled in a land where they found safety and stability, that the Negus had prevented anyone who sought to reach them from doing so, and that Umar had become Muslim, so that he and Hamza bin Abdul-Muttalib were now with the Messenger of Allah and his companions, and that Islam had begun to spread among the tribes, they gathered together and conspired among themselves to write a document binding themselves against Banu Hashim and Banu Abdul-Muttalib, agreeing that they would not marry into them nor let them marry into them, that they would not sell anything to them, and that they would not buy anything from them.When they had agreed on this, they wrote it down in a document, then they pledged and bound themselves to it, and then they hung the document inside the Kaaba as a means of binding themselves firmly to it. The one who wrote the document was Mansur bin Ikrima bin Amir bin Hashim bin Abd Manaf bin Abd Dar bin Qusayy."Ibn Ishaq said, "When Quraysh did this, Banu Hashim and Banu Muttalib withdrew to Abu Talib bin Abdul-Muttalib and entered his quarter with him, gathering around him. But Abu Lahab, Abdul-Uzza bin Abdul-Muttalib, one of Banu Hashim, went out to Quraysh and sided with them." [Sirat bin Hisham, 1/350-351]Musa bin Uqba said, "They remained in that state for three years, until they were reduced to hardship, and nothing in the way of provisions reached them except in secret." That is, from the seventh year after the beginning of the mission to the tenth year after the beginning of the mission, about three years before the Hijrah.The biographers mention that a group then rose up to annul the document, the most determined among them in doing so being Hisham bin Amr bin Harith, Zuhayr bin Abu Umaya, Mutim bin Adi, Zama bin Aswad, and Abu Bakhtari bin Hisham bin Harith. What bound them to Banu Hashim and Banu Muttalib were ties of kinship.