He is Shaykh al-Islam Ahmad bin Muhammad bin Hanbal ash-Shaybani. He was originally from Baghdad. His grandfather Hanbal was one of the supporters of the Abbasid cause, and was the governor of Sarkhas during the Umayyad period. His father Muhammad was a soldier. His tribe was Shayban, which was known for courage and chivalry. Imam Ahmad was descended from a pure Arabic lineage that coincided with the lineage of the Prophet (ﷺ) in Nizar bin Ma'd bin 'Adnan, from (the clan of) Bakr bin Wa'il. His mother was Safiyyah bint Maymunah, who was also from the tribe of Shayban, from the clan of Banu 'Amir.

Imam Ahmad was born and raised in Baghdad. He was born in Rabee ul-Awwal 164 AH. His father Muhammad died young at the age of thirty, and Imam Ahmad was raised as an orphan, which is the reason why he learned to be self-reliant from childhood.

His Seeking Knowledge

When he finished his primary education (the kuttab) and reached the age of fourteen, he began to attend study circles at a higher level of education (in the deewan). Then he began to focus on studying hadeeth in 179 AH. First of all he studied with Imam Abu Yusuf al-Qadi. He missed out on studying with Ibn al-Mubarak when he came to Baghdad (he did not meet him because Ibn al-Mubarak had already departed on a campaign against the Byzantines). And he remained close to Hushaym bin Basheer until the latter died (183 AH). In this study circle he also heard of the death of Imam Malik. Then he went to Kufa where he became famous as an authority on reports narrated from Hushaym. He memorised all the books of Wakee', and was held in high esteem by Imam Wakee'. He left for Basrah in 186 AH, where he wrote down three hundred thousand ahadeeth from Bahz bin Asad (d. 197 AH) and 'Affan (d. 220 AH). The narrator said: I think he said: and Rawh bin 'Ubadah (d. 205 AH). He travelled to the Hijaz in 191 AH and returned to Basrah in 194 AH, where he attended the circle of Sa'eed al-Qattan. Then he went to Wasit, where he learned from Imam Yazeed bin Harun. He returned to Makkah in 197 AH, where he led a study circle in Masjid al-Khayf and issued many fatawa there when Ibn 'Uyaynah was still alive.

His Teachers and Students

His shuyukh numbered two hundred and eighty-odd, as was stated by adh-Dhahabi. He listed sixty-six people who learned from him, and he referred to others when he said: And a great many others besides them (Siyar, 11/181). Then he mentioned his senior students who wrote down from him numerous fatawa on various issues in many volumes, of whom there were approximately fifty, including al-Marwazi, al-Athram, Ibn Hani', al-Kawsaj, Abu Talib, his son Salih bin Ahmad and his brother Abdullah, their cousin Hanbal, Abu Dawood as-Sijistani and Isma'eel bin Umar as-Sijzi al-Hafidh. Abu Bakr al-Khallal narrated what these scholars had recorded of the opinions and fatawa of Ahmad, and wrote about one hundred of Ahmad's companions (As-Siyar by adh-Dhahabi).

His Narration of Hadeeth and Fatawa

By the time he reached his forties, in 204 AH, he was a prominent figure in the fields of Hadeeth and Fatawa, and people began to travel to learn from him. His last journey was in 209 AH, after which he did not leave Baghdad until the time of the Mihnah (testing) came.

His Methodology in Issuing Fatawa 

As he (رحمه الله) said:

There is no choice but the Sunnah and following it. And analogy should only be based on comparing something to an established principle (a precedent from the time of the Prophet ﷺ). But to come to the principle and demolish it and then say this is by analogy - on what basis are you making your analogy?

In other words, he (رحمه الله) would reject the idea of analogy and object to it if it was not based on a sound proven precedent.

His respect for the scholars of hadeeth is reflected in the following quotation from him:

Whoever holds the scholars of hadeeth in high esteem, the Messenger of Allah (ﷺ) will hold him in high esteem; whoever looks down on them will have no value in the eyes of the Messenger of Allah (ﷺ), because the scholars of hadeeth are the most knowledgeable about the way of the Messenger of Allah (ﷺ).

From the comments of His Excellency Dr. Abdullah bin Abdul-Muhsin at-Turki in Tahqeeq al-Musnad, p. 17-18.

lbn aI-Qayyim described the main foundation on which Imam Ahmad based his fatawa:

The texts (Qur'an and Sunnah), then the fatawa of the Sahabah, then selecting one of the views of the Sahabah if they differed, then following a mursal or da'eef ahadeeth (which in his view were valid and were categories of hasan ahadeeth). Then if he did not find any text concerning the issue, or any opinion of the Sahabah or one of them, or any mursal or da'eef report, he would resort to the fifth option, which is analogy (qiyas), and he would use it when necessary.

His Writings

The books attributed to Imam Ahmad are as follows:

1. Al-Musnad, published repeatedly.
2. Al-Illal Wa Ma'rifatur-Rijal, it is mentioned by al-Uqayli in ad-Du'afah that he read it upon Abdullah from his father. Published in two parts.
3. Fadha'il as-Sahabah, it contains additions from his son Abdullah and Abu Bakr al-Qutay'ee. Published in two volumes with the Tahqeeq of Wasi-Ullah Abbas by Mu'asasat ar-Risalat, Beirut.
4. At-Tafseer, mentioned by Ibn Nudaym and Ibn al-Jawzi, and it is related from az-Zajaj in Ma'ani al-Qur'an where he said therein (4/166): "Majority of what I narrated in this book in Tafseer is from the book at-Tafseer by Ahmad ibn Hanbal." He also said in another place (4/8): " We narrated from Ahmad ibn Hanbal - May Allah have Mercy on him - in his book Kitab at-Tafseer and it is what Abdullah, his son, permitted for me". Nevertheless, it was rejected by Imam adh-Dhahabi in As-Siyar (11/332, 13/325).
5. An-Nasikh w'al-Mansukh, It's photocopy is in Shaykh Hammad al-Ansari's library in Madinah.
6. Az-Zuhd, Ibn Hajr said in Ta'jeel al-Manfa'ah: "It is a large book, a third of the size of Al-Musnad and in it is a great amount of ahadeeth and athar which is not in Al-Musnad". 
7. Al-Fara'idh, mentioned by Ibn Nudaym. Adh-Dhahabi said in As-Siyar (11/228): "I saw a page from this book" and in Al-Manaqib (613) by Ibn al-Jawzi he indicates that it was with Ibrahim al-Harbi and he used to narrate it to the people.
8. Al-Asami Wa'l-Kina, It's published.
9. Hadeeth Shu'bah, mentioned by Ibn al-Jawzi and al-Khateeb al-Baghdadi in Tarikh Baghdad (9/375).
10. At-Tareekh, mentioned by Ibn al-Jawzi.
11. Al-Wara', it is attributed to him, however it is not from his writings, rather it is written by Abu Bakr al-Marrudhi (his student). It is published.
12. Ar-Rad Ala' az-Zanadaqah Wa'l-Jahmiyyah, it's been printed many times.
13. Kitab Ahl ar-Riddah Wa'z-Zanadaqah, it's available in Makkah in the possession of Muhammad Hamzah, and a photocopy of it is in Cairo. See Tarikh at-Turath al-Arabi (3/225) by Fuat Sezgin. It is published.
14. Al-Iman, mentioned by Ibn Abu Hatim in Al-Jarh Wa't-Ta'deel (1/353) and there's a manuscript of it available in The British Museum. See Tarikh at-Turath al-Arabi (3/229) by Fuat Sezgin.
15. Ta'at ar-Rasul, mentioned by Ibn Nudaym.
16. Al-Imamah, mentioned by adh-Dhahabi in As-Siyar (11/335) and he said: "A small volume".
17. Nafi at-Tashbih, mentioned by adh-Dhahabi in As-Siyar (11/335) and he said: "A volume".
18. Al-Muqadam Wa'l-Mu'akhir Fi'l-Qur'an, mentioned by al-Khateeb in Tarikh Baghdad (9/375). And in the biography of al-Marwazi from At-Tabaqat (1/62) by Ibn Abu Ya'la there is some of its content.
19. Jawabat al-Qur'an, mentioned by al-Khateeb in At-Tarikh (9/375).
20. Al-Manasik al-Kabir, mentioned by Ibn Nudaym.
21. Al-Manasik as-Saghir, mentioned by Ibn al-Jawzi.
22. Al-Ashribah, mentioned by Ibn Abu Hatim in Al-Jarh Wa't-Ta'deel (1/303). It is published.
23. Al-Wuquf Wa'l-Wisaya, it reached us from within Al-Jami' by al-Khallal and it is published.
24. Ahkam an-Nisa', it reached us from within Al-Jami' by al-Khallal and it is published.
25. At-Tarajjul, it reached us from within Al-Jami' by al-Khallal and it is published.
26. Al-Irja', it reached us from within Al-Jami' by al-Khallal.
27. Al-Fitan, there is a copy of it in Adh-Dhahiryyah Library in Damascus. It is published.
28. Fadha'il Ahl al-Bayt, mentioned by al-Hakim in Al-Mustadrak (3/157).
29. Musnad Ahl al-Bayt, taken out from Al-Musnad and it is published.

The following are treatises that are attributed to Imam Ahmad:

1. Risalah as-Sunnah, also known by Risalah al-Istakhree. Narrated by Ibn Abu Ya'la in At-Tabaqat (1/24-36).
2. A treatise he wrote al-Mutawakkil regarding the issue of the Qur'an being created. Narrated by Abu Na'eem in Al-Hilyah (9/216-219) and in that route it was narrated by Ibn al-Jawzi and adh-Dhahabi and he praised it's isnad on the level of hasan.
3. Risalah al-Hasan bin Isma'eel ar-Rabee, it's extremely short. Ibn Abu Ya'la included it in At-Tabaqat (1/130).
4. Risalah Abdus ibn Malik al-Attar, it's lengthy. Ibn Abu Ya'la included it also (1/241-246).
5. Risalah Muhammad ibn Awf at-Ta'ee, it's lengthy. Related by Ibn Abu Ya'la (1/311-313).
6. Risalah Muhammad ibn Yunus as-Sarkhasi, included by Ibn Abu Ya'la (1/329-330).
7. A treatise to Musaddad bin Musarhid al-Basri (D. 228H) which is lengthy, related by Ibn Abu Ya'la (1/342-345).
8. Risalah Fi's-Salah, he wrote it to Muhanna bin Yahya ash-Shami, like what is in At-Tabaqat (1/348-380). And it's attribution to Imam Ahmad is a fabrication like what adh-Dhahabi said (11/287,330), and the one who reads it will find that it contradicts his style and method, and what confirms this is the saying of adh-Dhahabi. However some contemporary scholars such as Shaykh Bakr Abu Zayd and Shaykh Hamud at-Tuwayjiri dispute this. A written copy of it is available in the Public Endowments Library in Baghdad with the number (2/13853) consisting of 9 sheets, and another copy with the number (1/6786) consisting of 12 sheets. It is printed in Egypt with the title Ar-Risalah As-Sunniyyah Fi's-Salah Wa Ma Yalzimu Feeha Li'l-Imam.

His Testing (Mihnah) Concerning the Issue of Whether the Qur'an Was Created

Imam Ahmad continued to narrate hadeeth and issue fatawa until 218 AH, when the Caliph al-Ma'mun declared his view that the Qur'an was created and issued orders that the scholars be tested concerning their opinions on this issue. But Imam Ahmad remained steadfast in his view that the Qur'an is the words of Allah and was not created. He was taken to al-Ma'mun in chains, but when he reached ar-Raqqah, news came of the death of al-Ma'mun (218 AH). He was succeeded by the Caliph al-Mu'tasim, and Imam Ahmad remained in prison in Baghdad until the death of al-Mu'tasim in 227 AH. Al-Mu'tasim was succeeded by al-Wathiq, who revived the practice of testing scholars with regard to the issue of whether the Qur'an was created. Imam Ahmad isolated himself from people and stayed in his house, not going out to pray or for any other purpose, until al-Wathiq died (232 Al-I). Two years after al-Mutawakkil became caliph, he issued orders that the testing of scholars be stopped, and he began asking the scholars of hadeeth to come to Samarra' to hold study circles in which they would teach hadeeth. Imam Ahmad came to Samarra' in 235 AH, but al-Mutawakkil ordered him to go back to Baghdad.

Imam Ahmad had stopped teaching hadeeth since al-Wathiq became caliph (225 AH approx.); he did not narrate any hadeeth except to his two sons. During this period he was free to narrate this great book, Al-Musnad, to his two sons, Salih and 'Abdullah, and his paternal cousin Hanbal bin Ishaq, between the years 225-227 AH. It is known that no one heard the Musnad in its entirety except these three.

In 227 AH, al-Mutawakkil summoned Imam Ahmad to Samarra' again, but the Imam realised that he would be detained there (i.e., he would be forced to remain in the city). He was distressed by that, but as he had no choice but to go to him, he refused to buy a house or to teach hadeeth; he had made a promise to Allah that he would not narrate any hadeeth in complete form until he met him, and he did not make an exception from this promise even for his two sons. He began to wish for death; he would say, clenching his fist: "If my soul were in my hands, I would have released it," then he would open his fist. This does not mean that he gave up completely on discussing issues of knowledge; rather he spent the rest of his life discussing fiqh, reports and the biographies of narrators, until his death. (Quoted from Tahqeeq al-Musnad, Introduction, P38-45).

Among the things he said when he was being tested during the Mihnah was:

lf the scholar remains silent on the grounds of dissimulation (Taqiyyah), and the ignorant do not know, then when will the truth be manifested?

His Death

He was ill for nine days, as al-Marwazi said, and he died in the morning on 12 Rabee' ul-Awwal 241 AH in Baghdad, where he was buried. He was seventy-seven years old. His funeral was attended by many, as Abdul-Wahhab al-Warraq said:

We have never heard of a gathering like it, in the Jahiliyyah or in Islam. The best estimate is one million mourners, and we estimate that the number of women around the graves was sixty thousand.

It is through gatherings like this that truth is established, as Imam ad-Daraqutni narrated from Sahl bin Ziyad, who said:

I heard Abdullah bin Ahmad say: I heard my father say: 'Say to the followers of innovation: the judge between us and you is the day of funerals.'

Praise of the Scholars For Him

Imam ash-Shafi'ee said:

Ahmad bin Hanbal was a leading scholar in many fields: in Hadeeth, in Fiqh, in Qur'an, in Zuhd (asceticism), in piety and in knowledge of the Sunnah.

Abdul-Malik al-Maymuni used to say:

My eyes never saw anyone better than Ahmad bin Hanbal, and I have never seen anyone among the scholars of hadeeth who shows more respect for the sacred limits of Allah and the Sunnah of His Prophet, if (a report) is proven to be saheeh. And i have never seen anyone more keen to follow (the Sunnah) than him.

Al-Marwazi said:

I said to Ahmad: 'How are you this morning?' He said: 'How would anyone he whose Lord is demanding that he carry out the obligatory duties, and his Prophet is demanding that he follow the Sunnah, and the two angels are demanding that he mend his ways, and his nafs is demanding that he follow its whims and desires, and lblees is demanding that he commit immoral actions, and the angel of death is watching and waiting to take his soul, and his dependents are demanding that he spend on their maintenance?'

An-Nawawi narrated in Tandheeb a-Asma' wal-Lughat, as did adh-Dhahabi in Siyar Alam an-Nubala', from Qutaybah bin Sa'eed that he said:

When ath-Thawri died, piety died; when ash-Shafi'ee died, proper adherence to the Sunnah died; when Ahmad died, innovation (bid'ah) emerged.

Ibn Ma'een said:

The people wanted us to be like Ahmad bin Hanbal. No, by Allah! We are not as strong as Ahmad and we are not strong enough to follow the way of Ahmad. (Ahmad bin Hanbal Bayna Mihnatid-Deen wa Mihnatid-Dunya, Ahmad ar-Rumi, p. 15.)

Adapted from Musnad Imam Ahmad Vol.1 pp. 15-21 & https://www.saaid.net/bahoth/267.htm.