Bukhari And Muslim
8. Why are not the traditions about the succession of ‘Ali in Sahih Bukhari and Muslim?
Answer:
It did not agree with their personal views
The reason why both shaykhs [Bukhari and Muslim], and their likes, have not quoted this hadith is because 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.
Anyone who knows the behavior of Bukhari and his attitudes towards the Commander of the Faithful and other members of Ahl Al-Bayt (‘a), will know that his 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.