Imam A'zam Abu Hanifa, Imam Maalik, Imam Shaafi and Imam Ahmed bin Hambal (radi Allahu anhumul ajma'in)are the leaders of the four schools of Fiqh (Islamic Law).
"FIQH" is the Science of Islamic Law or Jurisprudence. It refers to the collection and compilation of Islamic laws based on the Holy Quran and the Sunnah of Sayyiduna Rasulullah (sallal laahu alaihi wasallam). These great Muslims devoted themselves to the task of developing the science of understanding Islamic Law and its practise.
Although they differed from each other, all the four great Imams had great respect for each other. They were all teachers and pupils of each other for the common goal of enhancing their knowledge about Islam. All of them were unanimous on Aqa'ids (Islamic Beliefs). We, as Muslims, must respect the different Sunni schools of thought.
Imam Abu Abdullah Ahmed bin Mohammed bin Hambal (radi Allahu anhu) was born in Marw on the 20th of Rabi-ul-Awwal 164 A.H.
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 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.
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.