Who was the Companion who sent a letter to Quraish informing them of the Messenger's arrival to conquer Makkah, and what is the full story behind that, and what is the reason for the Messenger of Allah (peace and blessings be upon him) saying: "Perhaps Allah looked upon the hearts of the people of Badr..."?

The Companion who sent a message to Quraysh informing them that the Messenger of Allah, peace and blessings be upon him, was coming to conquer Mecca, was Hatib ibn Abi Balta'ah, may Allah be pleased with him. This is affirmed in the agreed-upon Hadith (definition), where Hatib sent a letter to the people of Mecca informing them of some of the Messenger of Allah's affairs, peace and blessings be upon him. He justified his action by stating that he wanted to have a favor with them to protect his family and wealth in Mecca, and that it was not an act of disbelief or apostasy. The Prophet, peace and blessings be upon him, believed him and said to Umar, who had requested to kill him: "Indeed, he participated in Badr, and how do you know, perhaps Allah has looked upon the people of Badr and said: 'Do as you wish, for I have forgiven you.'" And Allah, the Almighty, revealed concerning this matter: {O YOU WHO HAVE BELIEVED, DO NOT TAKE MY ENEMY AND YOUR ENEMY AS ALLIES} (Al-Mumtahanah: 1).