Banu Hashim
...Islam began to spread among the tribes. The Quraysh realized that Banu-Hashim and Al-Muttalib were determined to protect the prophet and defend him so they gathered together to confer and decided to draw up a document in which they undertook not to marry women from Banu Hashim and Banu al Muttalib, or to give them women in marriage, or to sell anything to them or buy anything from them. They drew up a written contract to that effect and solemnly pledged themselves to observe it. They then hung up the document in the interior of the Kaaba to make it even more binding upon themselves. When Quraysh did this, the Banu Hashim and the Banu al-Muttalib joined with 'Abu Talib, went with him to his valley and gathered round him there; but 'Abu Lahab 'Abd al Uzza b. 'Abd al-Muttalib left the Banu Hashim and went with the Quraysh supporting them against 'Abu Talib. This state of affairs continued for two or three years, until the two clans were exhausted, since nothing reached any of them except what was sent secretly by those of the Quraysh who wished to maintain relations with them".