What is the level of authenticity of the book, Al Adabul Mufrad’? Are there some very weak Hadiths inside?
In principle, if an author does not mention that he will mention/report all reliable narrations in his book then every narration will have to be inspected individually. It is not possible to pass a blanket ruling on all the narrations found therein.
Although Imam Bukhari (rahimahullah) did not mention that he will only narrate reliable narrations in his Al Adabul Mufrad, one can safely say that majority of the Hadiths found therein are authentic or at least, suitable for practice.
Imam Darimi (rahimahullah) had inspected Imam Bukhari (rahimahullah)’s Al Adabul Mufrad for three months. He was then asked, ‘Did you come across any weak narrations therein?’ He replied ‘Ibnu Isma’il [i.e. Imam Bukhari] only reports authentic narrations to the people, and who can criticize Muhammad [ibn Isma’il Al Bukhari]
(Siyaru A’alamin Nubala, vol. 12 pg. 427. Also see Fadlullahis Samad vol. 1 pg. 23, for further beneficial notes on this topic)
With regard to the next part of your question, Imam Bukhari (rahimahullah) has recorded approximately 1322 Hadiths in his Al Adabul Mufrad. From this total, many narrations are found in either Sahih Bukhari or Sahih Muslim, and are therefore authentic.
A contemporary Scholar has claimed to have come across only seven (7) very weak narrations for which he couldn’t find support. I have not gone through these narrations to verify this claim.
(Refer: Zawaidul Adabil Mufrad ‘Alas Sahihayn, pg. 19)
And Allah Ta’ala Knows best.
Answered by: Moulana Suhail Motala
Approved by: Moulana Muhammad Abasoomar, with the following comment:
It is highly possible that after researching even these seven that are claimed to have remained weak, someone else may find sufficient support which would render these too as reliable, even though this contemporary Scholar didn’t manage such.
The field of Hadith research is prone to such variant conclusions.
Checked by: Moulana Haroon Abasoomar