The four imaams offered a great service in the field of fiqh and their heritage is great value to the ummah. The fourth of them:

Imaam Ahmad bin Hanbal

He is Ahmad bin Muhammad bin Hanbal al-Shaybaaanee from the tribe of Rabee'ah al-Adnaaniyyah. He was born in 164H and died in 241H. From this most well-known teachers:

• Al-Qaadee Abu Yusuf (d. 182H)
• Hushaym bin Basheer Abee Haazim al-Waasitee (d. 183H)
• Sufyaan bin Uyainah (d. 198H)
• Abd al-Razzaaq bin Hammaam (d. 211H)
• Al-Waleed bin Muslim
• Abd al-Rahmaan bin Mahraan
• Yahyaa al-Qattaan

From his most well-known students:

• Ahmad bin Muhammad bin Haani al-Athram (d. 260H)
• Saalih, his eldest son (d. 266H)
• Abu Bakr Ahmad bin Muhammd bin Haani al-Baghdaadee (d. 273H)
• Abd al-Malik bin Abd al-Hameed bin Mahraan al-Maymoonee (d. 273H)
• Ahmad bin Muhammad bin Hajjaaj al-Marwazi (d. 275H)
• Abdullah bin Ahmad bin Hanbal (d. 290H)

The foundations of his madhhab:

• The Noble Qur'an
• The Prophetic Sunnah
• The fataawaa of the Companions
• Choosing from the fataawaa of the Companions where they differed
• Making use of the mursal and da'eef hadeeth (with conditions and restrictions)
• Use of analogy (qiyaas) but out of necessity.

Spread of his madhhab:

• Concentrated in Najd specifically and more generally in Saudi Arabia
• Palestine
• Shaam (Syria, Jordan)
• Iraq

Most famous books of the madhhab:

• Al-Mughnee of Ibn Qudaaamah (d. 620H)
• al-Iqnaa' of al-Hajaawee (d. 968H)

Refer to (الملخصات الفقهية الميسرة) "Simple, Summarized Fiqh Principles" (Imaad Ali Jumu'ah, 1434H, Dar al-Nafaa'is).