Imam Abu Abdullah Ahmed bin Mohammed bin Hambal (Rahimahu Allahu Ta'ala) was born in Marw on the 20th of Rabi-ul-Awwal 164 A.H.
EARLY LIFE: His father, Sayyiduna Mohammed (radi Allahu anhu) was a warrior (Mujaahid) and lived in Basrah, Iraq. Imam Ahmed bin Hambal (radi Allahu anhu) was a very intelligent child, keenly interested in furthering his Islamic education. At the age of 16, he began studying Hadith literature. It is said that he learnt almost a million Ahadith by heart. He became a famous Jurist.
HIS TEACHERS: Some of his teachers were Imam Shaafa'ee, Sayyiduna Bishar bin Al Mufaddal, Sayyiduna Ismail bin Ulayyah, Sayyiduna Jarir bin Abdul Hamid and Sayyiduna Yahya bin Said (radi Allahu anhumul ajma'in). The great compilers of Ahadith, Imam Bukhaari and Imam Muslim (radi Allahu anhuma), including his teacher, Imam Shaafa'ee (radi Allahu anhu), have also reported Hadith from him. Imam Shaafa'ee (radi Allahu anhu), in spite of being the most learned in his time, used to refer to Imam Ahmed bin Hambal (radi Allahu anhu) about certain Ahadith.
HIS PUPILS: Amongst his pupils, the most famous were Sayyiduna Abu Bakr Al Alhram, Sayyiduna Hambal bin Ishaaq and Sayyiduna Abul Qasim Al Baghwi (radi Allahu anhumul ajma'in).
HIS PIETY: Imam Ahmed bin Hambal (radi Allahu anhu) was a very pious scholar who devoted all his life in the Science of Ahadith and Fiqh. He refused to eat in anyone's house who held a Governmental post. Being extremely poor with no food to eat at times, he used to still refuse to accept charity saying that he had full faith in Almighty Allah.
HIS WORKS: The most famous among his books are: Kitaabul A'maal, Kitaabut Tafseer, Kitaabul Naasikh wal Mansookh, Kitaabul Zahid, Kitaabul Masaa'il, Kitaabul Fadaa'il and Kitaabul Mansiq. His most famous book is his "MUSNAD", a kitab in which he collected about 50 000 to 70 000 Ahadith.
IMPRISONMENT: Imam Ahmed bin Hambal (radi Allahu anhu), in the later years of his life, was imprisoned and tortured by the ruthless rulers who went against him due to their un-Islamic beliefs and practises. Caliph Mutasim billah forced the Imam to accept the beliefs of the "Mu'tazalis" (a corrupt sect), but he refused, and was beaten to such a degree that his joints were dislocated. He was kept in heavy chains for 30 months in a prison in Baghdad. He still refused to accept the beliefs of the corrupt Mu'tazali Sect and was again beaten till he fell unconscious.
PASSES AWAY: On the 25th of Ramadaan in the year 221 A.H., Caliph Mutasim, in fear of the sin he committed, repented and set the Imam free. Imam Ahmed bin Hambal (radi Allahu anhu) forgave all the people except the Mutazalis. He passed away in the year 241 A.H.
Ref: http://www.islamcan.com/