Abu Basir said to one of them, `By Allah, O, so-and-so, I see you have a fine sword.' The other drew it out (of its sheath) and said, `Yes, by Allah, it is very fine and I have tried it many times.' Abu Basir said, `Let me have a look at it.' When the other gave the sword to Abu Basir, he struck him with it until he died. His companion ran away until he reached Al-Madinah, entering the Masjid running. When Allah's Messenger saw him he said,
«لَقَدْ رَأَى هذَا ذُعْرًا»
(This man appears to have been frightened.) When he reached the Prophet he said, `My companion has been murdered, by Allah, and I would have been murdered too. ' Abu Basir came and said, `O Allah's Messenger, by Allah! Allah has made you fulfill your obligations by returning me to them, but Allah the Exalted has saved me from them.' The Prophet said,
«وَيْلُ أُمِّهِ مِسْعَرَ حَرْبٍ لَوْ كَانَ مَعَهُ أَحَد»
(Woe to his mother! What an excellent war kindler he would be, if he only have supporters.) When Abu Basir heard this from the Prophet , he understood that he would return him to the idolators again, so he set off until he reached the seashore. Abu Jandal bin Suhayl also got himself released from the disbelievers and joined Abu Basir.
Thereafter, whenever a man from Quraysh embraced Islam he would follow Abu Basir until they formed a strong group. By Allah, whenever they heard about a caravan of the Quraysh heading towards Ash-Sham (Greater Syria), they stopped it, attacked and killed the disbelievers and took their properties [they were not directly involved with the Muslims in Medinah, so the Muslims in Medinah were not responsible for these attacks].
The people of Quraysh sent a message to the Prophet requesting him for the sake of Allah and kith and kin to send for (Abu Basir and his companions) promising that whoever among them came to the Prophet , would be secure. So, the Prophet sent for them and Allah the Exalted and Most Honored revealed the following Ayat,
[وَهُوَ الَّذِى كَفَّ أَيْدِيَهُمْ عَنكُمْ وَأَيْدِيَكُمْ عَنْهُم بِبَطْنِ مَكَّةَ]
(And He it is Who has withheld their hands from you and your hands from them in the midst of Makkah), until,
[حَمِيَّةَ الْجَـهِلِيَّةِ](the pride and haughtiness of the time of ignorance, )
Their pride and haughtiness was that they did not confess that Muhammad was the Prophet of Allah, refused to write, `In the Name of Allah, Ar-Rahman, Ar-Rahim,' and prevented Muslims from visiting the Ka`bah.''
Surah al Fath; Tafsir ibn Kathir;
So the part of contract of the Muslims from Makkah being deported back - if they escaped - was cancelled by the Quraysh themselves, because of the great harm they recieved through it. A true moral victory for the Muslims.