1) Have I not ascertained its reliability by Sunnis, I would not have mentioned it to you. Yet Ibn Jarir and Imam Abu Ja`fer al-Iskafi have taken its authenticity for granted. Several other critics have also considered it authentic. It is sufficient proof for its authenticity the fact that it is reported by the reliable authorities upon whose accuracy the authors of sahih books rely unhesitatingly. Refer to page 111, Vol. 1, of Ahmed's Musnad, where you will read this hadith as narrated by Aswad ibn `Amir from Sharik, al-A`mash, Minhal, `Abbad ibn `Abdullah al-Asadi, from `Ali (as) chronologically. Each one of these men in the chain of narrators is an authority in his own right, and they all are reliable traditionists according to the testimony of the authors of the sahih books without any dispute. Al-Qaysarani has mentioned them in his book Al-Jami` Bayna Rijal al-Sahihain. There is no doubt that this hadith is authentic, and the narrators report it from various ways each one of which supports the other.
2) The reason why both shaykhs [Bukhari and Muslim], and their likes, have not quoted this hadith is due to the fact that it did not agree with their own personal views regarding the issue of succession. This is why they have rejected a great deal of authentic texts for fear the Shi`as may use them as pretexts; therefore, they hid the truth knowingly. There are many Sunni shaykhs, may Allah forgive them, who have likewise hidden such texts, and they have in their method of hiding a well known history written down by al-Hafiz ibn Hajar in his Fath Al-Barari. Al-Bukhari has assigned a special chapter for this theme at the conclusion of his chapter on "Al-`Ilm," in Vol. 1, page 25, of his Sahih, subtitled "A Chapter on Those Who Recognized the Knowledge of some People Rather than that of Others."
3) Whoever knows the way al-Bukhari thought, his own attitudes towards the Commander of the Faithful (as), and towards all Ahl al-Bayt (as), will come to know that Bukhari's pen falls short of narrating texts regarding them, and his ink dries up before recounting their attributes. He will not be surprised to see him rejecting this particular hadith as well as others similar to it; therefore, we seek refuge with Allah, the Almighty, the Sublime, and peace be with you.
 Refer to hadith 6045 of the hadith included in Kanz al-`Ummal, page 396, Vol. 6, where you will find reference made to Ibn Jarir's verification of this hadith. If you refer to Muntakhab al-Kanz, the beginning of the footnote on page 44, Vol. 5, of Ahmed's Musnad, you will find reference to Ibn Jarir's verification of this hadith. As regarding Abu Ja`fer al-Iskafi, he has emphatically judged its accuracy in his book Naqd al-`Uthmaniyya; so, refer to the text of page 263, Vol. 3 of Sharh Nahjul Balaghah by al-Hadid, Egyptian edition.
 Both al-Bukhari and Muslim have relied on him in their sahihs. They have both learned hadith from Shu`bah, and Bukhari has learned it from `Abdul-`Aziz ibn Abu Salamah, while Muslim has learned hadith from Zuhayr ibn Mu`awiyah and Hammad ibn Salamah. His hadith is narrated in Bukhari by Muhammad ibn Hatim ibn Bazi`. In Muslim's Sahih he is quoted by Harun ibn `Abdullah the critic, and by Abu Shaybah and Zuhayr.
 Muslim has relied on his authority in his Sahih, as we explained when we discussed him in Letter No. 16.
 Both Bukhari and Muslim rely on his authority in their respective sahihs, as we have stated while discussing him in Letter No. 16.
 Al-Bukhari has relied on him, as we explained when we mentioned him in Letter No. 16.
 His full name is `Abbad ibn `Abdullah ibn al-Zubayr ibn al-Awwam al-Qarashi al-Asadi. Al-Bukhari and Muslim rely on his authority in their respective sahihs. He has heard hadith from Asma' and `Ayesha daughters of Abu Bakr. He is quoted in both sahihs by Ibn Abu Malka, Muhammad ibn Ja`fer ibn al-Zubayr, and Hisham ibn `Umer.