One indication to Imam Abu Hanifah’s vast knowledge of the sources of the Shari’ah is his methodology in deriving rulings from the Shari’ah, since one of his primary sources is the authentic sunnah and the opinions of the Sahabah, as he himself explicitly stated:
Hafiz Ibn ‘Abd al-Barr narrates: ‘Abd al-Warith narrated to us: Qasim narrated to us: Ahmad ibn Zuhayr narrated to us: Yahya ibn Ma‘in narrated to us: ‘Ubayd ibn Abi Qurrah narrated to us from Yahya ibn Durays, he said: I was present with Sufyan al-Thawri when a man of great knowledge and piety came to him, and he said: “O Abu ‘Abd Allah! What do you have against Abu Hanifah?” He said: “And what does he have?” He said: “I heard him [i.e. Abu Hanifah] say a statement in which there is balance and proof: ‘Indeed I take [legal opinions] from the Book of Allah when I find it. That which I do not find therein, I take from the Sunnah of Allah’s Messenger and the authentic narrations from him which have spread between the hands of trustworthy people from trustworthy people. If I do not find it in the Book of Allah, nor the Sunnah of Allah’s Messenger, I take the opinion of his companions, [adopting the opinion of] whoever [of them] I wish, and I leave the opinion of whoever [of them] I wish. Moreover, I do not leave their opinion for another’s opinion. If the [legal] issue reaches [only] to Ibrahim, al-Sha‘bi, al-Hasan, ‘Ata, Ibn Sirin, Sa‘id ibn al-Musayyab – and he enumerated [other] men – then, [they are] a people who performed ijtihad, so I may perform ijtihad just as they performed ijtihad.’” Thereupon, Sufyan remained silent for a long period, and then he said some words of which there remained none in the gathering but he wrote them: “We hear harshness in speech and we fear it. We hear softness and we desire it. We do not judge the living; nor do we judge the dead. We accept what we hear. And we entrust what we do not know to its knower, and we put our opinion in doubt in favour of their opinion.” (Al-Intiqa’ fi Fada’il al-A’immati l-Thalathat al-Fuqaha’, pp. 264-5)
This sanad is authentic: ‘Abd al-Warith ibn Sufyan al-Qurtubi (d. 395) is thiqah according to al-Dhahabi in Siyar A’lam al-Nubala (Misbah al-Arib 2:297); al-Qasim ibn Asbagh al-Qurtubi (247 – 340) was called “the great hafiz” and “the muhaddith of Cordoba” by al-‘Asqalani and is saduq (Lisan al-Mizan (6:367-8); Ahmad ibn Zuhayr ibn Harb (d. 299) is thiqah according to al-Daraqutni and Khatib; ‘Ubayd ibn Abi Qurrah is a shaykh of Ahmad ibn Hanbal and is thiqah according to Ya‘qub ibn Shaybah and Yahya ibn Ma‘in (Tarikh Baghdad 12:386-9); Yahya ibn al-Durays (d. 203) is a narrator of Muslim, and is thiqah according to Ibn Ma‘in (Tahrir al-Taqrib 4:89).
Al-Khatib al-Baghdadi transmitted the same narration with a different chain leading up to Yahya ibn Ma‘in after which the chain is the same, and Dr. Bashshar ‘Awwad Ma‘ruf commented on it, “This is a report with a sahih isnad, and its narrators are trustworthy and well-known.” (Tarikh Baghdad 15:504)
Several other narrations with similar wordings from Imam Abu Hanifah about his methodology have been reported in al-Intiqa’ by Ibn ‘Abd al-Barr (pp. 266-7). These narrations from Imam Abu Hanifah regarding his methodology in deriving laws reveal the baselessness of the allegation that in most of his opinions he relied on analogy and parted from the transmitted sources of the Shari’ah. In fact, the Qur’an, well-known sunnah and narrations from the Sahabah were the primary foundations of his madhhab.