Even if he worked like a whole-time teacher...
Even if he worked like a whole-time teacher, during all these 23 years he did not have enough time at his disposal to impart all the teachings of Islam, especially in view of the fact that Islam is a complete code of human life particularly in our present age. Use of Analogy As a result of what they hold in this connection, the Sunnis had to face many practical difficulties in regard to the rules of Islamic law. They came across questions about which nothing was mentioned in the Qur'an.
They checked the collections of traditions which they had, but there also they did not find the answer. What to do then? To solve the problem they resorted to analogy which means to extend on the basis of some existing similarity the rule of a text to a case not provided for in the Quran and the Sunnah. For example we say that the law says so in that case. As this case is somewhat similar to that, the same rule should apply to this case also.
Possibly, in that case the Holy Prophet gave that particular order for such and such reason and as that reason exists in this case also, the same order should apply to it also. As may be seen, the analogical deduction is based on possibilities only. The cases where Prophetic traditions were not available were too many. The world of Islam greatly extended during the Abbasid period. Many countries were conquered.
Consequently new problems arose everyday; the solution of which was not found in the Qur'an and the Sunnah. The result was that analogical deduction became a regular practice. The Sunnis were divided into two groups. The first group which included Ahmad ibn Hambal and Malik ibn Anas, looked at analogical deduction with suspicion. It is said that Malik ibn Anas resorted to this process only in two cases. The other group which included Abu Hanifah made use of analogy on a too wide scale.
Abu Hanifah used to say that the sayings attributed to the Holy Prophet were not reliable. He declared that he found only fifteen Prophetic traditions trustworthy. In all other cases he resorted to analogical deduction. Shafi'i had a midway position. In some cases he relied on Prophetic traditions and in others he applied analogy, with the result that he produced a sort of hotchpotch code of law.