Doubt: The founders of the madhabs may have missed many of the hadith that we know of today. This is why we do not adhere to the madhabs.
Answer: This is a simplistic understanding which appears to make sense to the unsuspecting person but is far from accurate upon examination. Those who say that Imam Abu Hanifah did not know all of the hadith, and that ‘Sahih al-Bukhari’ was compiled after him are unaware that there are Hanafi scholars who had memorized ‘Sahih al-Bukhari’ and the other hadith collections. There are also unaware that it is common in many parts of the Hanafi world to study Sahih al-Bukhari and other books of hadith as part of their academic studies.
No One Can Gather All of The Sunnah Not Even Those Who Argue Against The Adherence to The Madhabs: No scholar can encompass all of the sunnah, not even Hafidh Ibn Hajar, Imam al-Nawawi, or even Sheikh al-Albani (May Allah have mercy upon all of them). Imam Ibn Taymiyyah said in ‘Raf al-Malam’ (p.17):
Whoever thinks that every Sahih hadith has reached everyone of the Imams, or a specific one of them, then he is mistaken.
Imam al-Biqai in ‘al-Nukat al-Wafiyyah’ (p.26/b) said quoting his teacher Hafidh Ibn Hajar (Allah have mercy on all of them) that:
It is not appropriate that any of the Imams be described as having gathered all of the hadith in terms of precisely memorizing. Such that it is mentioned that al-Shafi said: Whoever claims that the all of the sunnah has been gathered with one man: has transgressed (fasaq), and the one who says: Some part of it has been missed by the muslim community (ummah): has trangressed (fasaq).
Therefore it is not possible for anyone to claim for himself or others that he has collated all of the sunnah, and it does not necessitate that the Imam who knows most hadith is more deserving of being followed as someone maybe more proficient than others at deriving the rulings from the hadith, as has been mentioned before, memorization is one thing and understanding the content of the hadith is another. Imam Ibn Taymiyyah said in ‘Raf al-Malam’ (p.19):
It should not be said: The one who does not know all of the hadith is not a Mujtahid! because if its conditioned for a Mujtahid that he possess knowledge of what was said and practised by the Prophet (Allah bless him and give him peace) relating to legal rulings: Then according to this there is not in the Muslim community (ummah) a Mujtahid. The most for a scholar is for him to know the majority of it and most of it, such that he is not unaware except of a little of the detail.
One Hadith Containing 400 Points of Benefit: Everything from the Prophet (Allah bless him and give him peace) is a source from which we can derive many rulings related to the lawful and prohibited. To the extent that some have derived from the hadith “O Abu Umair what did the Nughair do” 400 points of benefits, many of which relate to legal rulings and the majority to adab. See Fath al-Bari (10:584) and Tartib al-Idariyyah of Sayyid Abd al-Hayy al-Kattani (2:150)
Someone Maybe Knowledgeable But Does Not Pass on Much of Their Knowledge: Abu Bakr al-Siddiq (Allah be pleased with him) was the first adult man to accept Islam and the closest companion of the Prophet (Allah bless him and give him peace), and the most knowledgeable of the companions, but along with this only a very little has come to us from his narrations which would suggest that he is a scholar from the scholars of the companions, let alone give the impression that he is the most knowledgeable of the companions. This is also the case with Sayyidina Umar, Uthman and Ali and also a large number of Tabieen and their students.
The Mujtahid Imam’s Did Not Narrate All That They Knew: This is also the case with Imam Malik, who as it is reported in Tartib al-Madarik (1:121) said:
I wrote 100,000 hadith with my own hands
Rather Allamah al-Zurqani in his commentary on the ‘Muwatta’ (1:7) reports that Imam Malik narrated 100,000 hadith, but look at the ‘Muwatta’ and see how many of these 100,00 hadith are contained in it?
This is likewise the case with Imam al-Shafi’s works which do not contain a large amount of material to suggest that he was a Muhaddith. The reason for this is that his and the other Mujtahid Imam’s focus was upon fiqh, deducing rulings and establishing the science of Usul al-Fiqh rather than narrating, and not because that they did not possess copious knowledge but that they had much knowledge but did not teach it all, this was also the case with Imam Abu Hanifah. As Al-Zabidi in ‘Uqud al-Jawahir al-Munifah’ (1:31) says:
Yahya bin Nasr said: I entered upon Abu Hanifah in a house full of books, I asked what are these? He said: These are hadith, I have only narrated a small amount of it that will be benefited from…
Mulla Ali al-Qari in his ‘Manaqib’ (2:474) mentions that Abu Hanifah mentioned 70 odd thousand hadith, and selected ‘al-Athar’ from 40,000 hadith.
Ibn Hajar al-Haitami in ‘al-Khairat al-Hisan’ (p.23) reports that al-Zaranjari said:
Imam Abu Hafs al-Kabir ordered the number of Imam Abu Hanifah’s Sheikhs to be counted, they reached 4,000 from the Tabieen.
Lack of Research And Not Jumping To Conclusions : Many people who have made these claims about the Imams knowledge of hadith do not actually go about to check the works of Imam Abu Hanifah or the Hanafi Imams to see whether or not they knew the hadith that they claim the Hanafi Imam’s have failed to act upon.
Sheikh Muhammad Awwamah in ‘Athar al-Hadith al-Sharif ‘(p.165) mentions that he heard some people of knowledge saying that Abu Hanifah did not know the hadith: ‘There is no prayers except with the fatihah of the book” despite the fact that it is reported by him in his well known ‘Musnad’ which has been published a number of times.
Not Finding the Hadith In an Imam’s Book Is Not a Proof That They Were Unaware of It: Even if someone does go through all the books of the Imams and does not find the exact hadith it is still not possible for him to negate the knowledge of the hadith that he is looking for from the Imam, as when you search for a Sahih hadith in al-Bukhari and Muslim and do not find it is not possible for you to negate the knowledge of that hadith for al-Bukhari and Muslim.
Also more importantly to negate for the Imams the knowledge of some hadith is to accuse someone of something without having full knowledge of the facts, it is more befitting for an intelligent muslim to accuse himself and blame himself for lack of research and understanding rather than to accuse the noble Imams of lack of knowledge of something which you claim to know, and what is more beautiful than what is reported by Imam al-Baihaqi in ‘Manaqib al-Shafi’ (2:154) from Imam Ahmad: Hammad bin Ahmad al-Basri said:
I was with Ahmad bin Hanbal and we were discussing the issue, a man said to Ahmad: O Abu Abdullah there is no authentic hadith regarding it! He –Ahmad said: Even if there is no authentic hadith with regards to it, there is the opinion of al-Shafi, and his proof is the most established thing with regards to it.