First of all, it is to be stated that the differences among the schools of Jurisprudence do not concern the major beliefs and practices of Islam, rather they properly belong to the area of furu’ or the details of religion. In fact, on a careful study, one would be inclined to assert that such differences among schools of jurisprudence are a true signs of vitality and dynamics of Islam.
Dr. Monzer Kahf, a prominent economist and counselor, states: “There is not really much of a difference between these schools of Fiqh. There are good sources in Arabic about the differences. The best source is the series by the late Imam Muhammad Abu Zahrah on the founders of these schools of Fiqh. There are actually more than four schools of Fiqh, but he has books about the four main schools (Hanafi, Shafi’i, Maliki, Hanbali schools). He also has texts about other schools and the founders of those schools.
Abu Hanifah’s school is usually described as the ra’y (opinion based on a thorough understanding of the spirit of Shari`ah) trend or the rationalist school. Ahmad is very much described as a main representative of the nass (text) trend. This doesn’t mean that there are no opinions in the Hanbali School and there is no (reliance on the) texts in the Hanafi School.
Imam Malik was a leader of combining both ra’y and nass together. One of his Sheikhs was Rabi`ah ibn Farrukh (who was known as Rabi`ah ar-Ra’y because of his work in developing the concept of ra’y in Madinah). Imam Malik got a lot from this teacher. At the same time, Malik has the first version of the authentic sayings of the Prophet in his book “Al-Muwatta'”. He was a leader in the text trend. In this way he combined both text and opinion.
Ash-Shafi`i, although he came before Ahmad (Ahmad was his student), was influenced by the text trend from Malik, but differed from Malik on the issue of deepening the opinion trend. In this sense, Ash-Shafi`i was more of a text follower than Malik.”