All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger.
The Enemies of Islam spare no effort to search for malicious allegations in order to call into question the religion of Allaah, but this is not strange coming from them as they are its enemies. However, a Muslim should have a firm belief in his religion and not have doubts about it because of these allegations whether or not he knows the answer to them. Also, if someone is not grounded in religious knowledge and does not have a firm belief, he should avoid reading or listening to such allegations as they might shake his belief.
As regards the allegation about the story or Umm Qirfah, then the book entitled Al-Mufassal Fi Ar-Radd ‘Ala Shubuhaat A’daa’ Al-Islam [The Detailed Response to the Allegations of the Enemies of Islam] written by the researcher ‘Ali ibn Naayif Ash-Shahood, reads: “This narration was reported in Tabaqaat Ibn Sa’d, and Ibn Al-Jawzi reported it from him in his book entitled Al-Muntathim, and the source of the narration is Muhammad ibn ‘Umar Al-Waaqidi, who was accused of lying according to the scholars of Hadeeth. The story was also reported in brief by Ibn Katheer in Al-Bidaayah Wan-Nihaayah, but he did not comment on it at all. Ibn Hishaam mentioned it as well in his book entitled As-Seerah; both of them narrated it from Muhammad ibn Is-haaq who did not mention the chain of narrators of this narration. To conclude, the narration is not authentic so it is not permissible to use it as evidence.” Then the author mentioned the statements of the scholars about Al-Waaqidi.
Also, Al-Haafith Ibn Hajar classified this narration, which reported the murder in this outrageous manner, as Dha’eef [weak], so he said in the book entitled Ad-Diraayah Fi Takhreej Ahaadeeth Al-Hidaayah: “Ad-Daaraqutni reported with an interrupted chain of narrators that Abu Bakr killed Umm Qirfah Al-Fazaariyyah and mutilated her body when she apostated.” However, it is known that an interrupted Hadeeth is classified among the categories of Dha’eef [weak] Ahaadeeth.
Al-Haafith Az-Zayla'i also classified it as Dha’eef in his book entitled Nasb Ar-Raayah Li Ahaadeeth Al-Hidaayah as he said: “Ad-Daaraqutni reported a Hadeeth on the authority of Sa’eed ibn ‘Abdul-‘Azeez that Abu Bakr killed Umm Qirfah Al-Fazaariyyah when she apostated and mutilated her body. He tied each of her legs to a horse and he shouted at them to go and they [horses] cut her into two parts. However, it was said that Sa’eed did not meet Abu Bakr, so this narration is interrupted.”
Moreover, Zayd ibn Haarithah is an honorable man who would not do such a thing to that woman, not to mention that mutilating the body of a killed person is forbidden in Islam. Buraydah narrated that among the advice of the Prophet to his Army commanders was: ''Fight (your enemy) but do not take from the booty before it is divided equitably, do not break the covenant, and do not mutilate and do not kill an infant….” [Muslim]
On the other hand, killing a woman in the war is forbidden in Islam unless she fights or instigates the fight and is helping the fighters, in which case, she is killed. Rabaah ibn Rabee’ said: “We were with the Prophet in a battle and he saw people gathered on something, so he sent a man to them and said to him: “Go and see on what these people are gathered." When the man came back, he said: “They gathered on a woman who was killed.” Thereupon, the Prophet said: “This woman should not have fought." He [the narrator] said: “Khaalid ibn Al-Waleed was leading the Army battalion that was at the front, so the Prophet sent a man to him and told him: “Tell Khaalid to kill neither a woman nor a hired servant.” [Ahmad and Abu Daawood]
Al-Bayhaqi said in As-Sunan As-Sughra, commenting on this Hadeeth: “This Hadeeth is evidence that if a woman fought, it would become permissible to kill her.”
As regards why At-Tabari, Ibn Is-haaq and others narrated this Hadeeth, then the answer is that the followed approach in history books is that they (the historians)write everything that was reported, but when providing a Hadeeth as evidence, they agreed that it is an obligation according to them to investigate it and make sure that the Hadeeth is authentic.
Allaah Knows best.