Once he has acquired this knowledge, he becomes qualified for independent legal reasoning and may issue fatwas and adjudicate. Whoever lacks this knowledge is not qualified for independent legal reasoning and may neither issue fatwas nor adjudicate. If he is appointed to the judgeship, his judgment is invalid—even if it accords with the correct ruling—because the condition is absent.

Knowledge that he is qualified for independent legal reasoning is established through prior acquaintance with him, by testing him, and by questioning him. The Messenger of Allah (peace and blessings be upon him) appointed ʿAlī to adjudicate in Yemen, but did not test him because he already knew him. Nevertheless, this served as guidance regarding the proper manner of adjudication. He said, “When the two litigants appear before you, do not decide in favor of either of them until you have heard what the other has to say.” ʿAlī said, “No case was unclear to me thereafter.”

He also sent Muʿādh to a region of Yemen and tested him. He asked him, “By what will you judge?” He replied, “By the Book of Allah.” He asked, “And if you do not find [the ruling] there?” He replied, “By the Sunnah of the Messenger of Allah (peace and blessings be upon him).” He asked, “And if you do not find it there?” He replied, “I will exercise my own legal reasoning.”