But ash-Shafi‘i found that even the addition of agreement to Qur’an and Prophetic usage did not give him basis enough for his system. Opinion he utterly rejected; the preference of Abu Hanifa and the conception of the common welfare of Malik ibn Anas were alike to him. It is true also that both had been practically saved under agreement. But he held fast by analogy, whether based on the Qur’an or on the usage of the Prophet. It was an essential instrument for his purpose. As was said, “The laws of the Qur’an and of the usage are limited; the possible cases are unlimited; that which is unlimited can never be contained in that which is limited.” But in ash-Shafi‘i’s use of analogy there is a distinction to be observed. In seeking to establish a parallelism between a case that has arisen and a rule in the Qur’an or usage, which is similar in some points but not precisely parallel, are we to look to external points of resemblance, or may we go further and seek to determine the reason (_illa_) lying behind the rule and from that draw our analogy? The point seems simple enough and the early speculative jurists sought the reason. For that they were promptly attacked by the traditionists. Such a method was an attempt to look into the mysteries of God, they were told; man has no business to inquire after reasons, all he has to do is to obey. The point thus raised was fought over for centuries and schools are classified according to their attitude toward it. The position of ash-Shafi‘i seems to have been that the reason for a command was to be considered in drawing an analogy, but that there must be some clear guide, in the text itself, pointing to the reason. He thus left himself free to consider the causes of the divine commands and yet produced the appearance of avoiding any irreverence or impiety in doing so. Such then are the four sources or bases (_asls_) of jurisprudence as accepted and defined by ash-Shafi‘i—Qur’an, prophetic usage, analogy, agreement. The last has come to bear more and more weight. Every Shafi‘ite law book begins each section with words to this effect, “The basis of this rule, before the agreement (_qabla-l-ijma_), is” Qur’an or usage as the case may be. The agreement must put its stamp on every rule to make it valid. Further, all the now existing schools have practically accepted ash-Shafi‘i’s classification of the sources and many have contended that a lawyer, no matter what his school, who does not use all these four sources, cannot be permitted to act as a judge. Ash-Shafi‘i has accomplished his own definition of a true jurist, “Not he is a jurist who gathers statements and prefers one of them, but he who establishes a new principle from which a hundred branches may spring.” [Sidenote: DA’UD AZ-ZAHIRI]