Causes of disagreement between scholars

Question: Why did the four Imaams (scholars) disagree on some legal matters? Did the Messenger of Allaah (peace be upon him) know that these Imaams would come after him?

Answer: We do not know whether the Messenger of Allaah (peace be upon him) knew that the four Imaams would come after him or not. This is because the Prophet (peace be upon him) did not know the Ghayb (the unseen), but knew only what Allaah informed him… read more here.