The Reason Due to Which Khalid ibn Walid Was Ordered to Murder Ali Ibn Abi Talib (as).
Abu Abdullah (ع) has said: When Abu Bakr prevented Fadak from Syeda Fatima (س) and threw out her representatives, Amirul Mo’minin (ع) came to the masjid and Abu Bakr was seated, and around him were the Emigrants and the Helpers.
So he (ع) said: ‘O Abu Bakr! Why did you prevent Fatima (س) from what Rasoolallah (ص) had made to be for her, and she had her representatives there for the last two years?’ So Abu Bakr said, ‘This is ‘Fey’ for the Muslims. So if she were to come with just witnesses then fine, or else there is no right for her in regards to it.’ He (ع) said, ‘O Abu Bakr! You are judging regarding us opposite to what you judge with regards to the rest of the Muslims?’ He said, ‘No.’
He (ع) said, ‘Inform me, if something were to be in the hands of the Muslims and I were to make a claim with regards to it, so from whom would you be asking for the proof?’ He said, ‘It is from you that I shall ask.’ He (ع) said, ‘So if there was something which was in my hands, and the Muslims are making a claim on it, you are now asking me for the proof?’ Abu Abdullah (ع) said, ‘So Abu Bakr was silent.’
So Umar said, ‘This is ‘Fey’ for the Muslims, and we are not going to dispute with you anything with regards to it.’ So Amirul Mo’minin (ع) said to Abu Bakr, ‘Do you acknowledge the Quran?’ He said, ‘Yes.’ He (ع) said, ‘So inform me about the Words of Allah (س) Mighty and Majestic:
But rather, Allah Desires to Keep away the uncleanness from you, O people of the House! And to Purify you with a Purification. [33:33]
Was it revealed regarding us, or others?’
Abu Bakr said, ‘Regarding you.’
He (ع) said, ‘If two witnesses from the Muslims were to testify against Fatima (س) for immorality, what would you do?’ He said, ‘I shall establish the punishment upon her just as I would against the Muslim women.’ Amirul Mo’minin (ع) replied, ‘Then you are from the Infidels, in the Presence of Allah (س).’ He said, ‘And why?’
He (ع) said, ‘Because you would have refuted the Testimony of Allah (س),and would be accepting the testimony of others, because Allah (س) has already Testified for her (س) Purification. So if you were to refute the Testimony of Allah (س) and accept the testimony of others, you would be, in the Presence of Allah (س), from the Infidels.’
Abu Abdullah (ع) said: So the people wept, and dispersed with tears in their eyes. So when Abu Bakr returned to his house, sent for Umar, so he said, ‘Woe be to you O son of Khattab! But you did not see Ali and what he did with us? By Allah! If he were to sit in another gathering, he would spoil the Caliphate against us, and we would not be welcome with anything as long as we are for alive.’ Umar said, ‘What is for him except Khalid bin Walid.’
So they sent for him, and Abu Bakr said to him, ‘We want to burden you with a great matter.’ He said, ‘Burden me whatever you so desire to, even for the murder of Ali.’ He said, ‘So it is the murder of Ali.’ He said, ‘So be at his side. When I finish the prayer, so strike his neck.’
So Asma bint Umays, and she is the mother of Muhammad bin Abu Bakr, called her maid and said, ‘Go to Fatima (س) and convey my greetings to her. So when she enters you into the door so say,
Surely the assembly is ordering for killing you, therefore depart; surey I am of those who wish well to you. [28:20]
So if she understands it, or otherwise repeat it to her once again.’ So she came, and entered, and said, ‘My mistress is saying, ‘O Daughter of Rasoolallah (ص)! How are you?’ Then she recited this verse, ‘Surely the assembly is ordering for killing you’. [28:20]
So when she wanted to leave, she recited it again. So Amirul Mo’minin (ع) said to her, ‘Convey greetings from me to your mistress, and say to her, ‘Allah, Mighty and Majestic would Turn around what is between them and between what they are intending for, if Allah so Desires it.’
So Khalid bin al-Walid paused by his side, intending Abu Bakr to finish the prayer. But he did not finish, and said, ‘O Khalid! Do not do what I had order you with! Peace be upon you and Mercy of Allah and His Blessings.’ So Amirul Mo’minin (ع) said, ‘What is this order which he had ordered you with, then prevented you before he greeted?’ He said, ‘He had ordered me with the striking of your neck. But rather, he had ordered me to do it after the greeting.’ So he (ع) said, ‘Or you would have done it?’ He replied, ‘Yes by Allah! Had he not prevented me, I would have done it.’
The Imam said: So Amirul Mo’minin (ع) stood up, seized the clothes of Khalid then hit him at the wall and said to Umar, ‘O son of Zahaak! By Allah! Had I not taken an oath from Rasoolallah (ص), and had the Book of Allah not been in front of me, you would have known where the weaker armies and the fewer numbers are.’
Illal al-Sharaie volume 1, part 6, p. 4-6