The difference between ethics and jurisprudence:
Morteza Agha Mohammadi
Both ethics and jurisprudence refer to the conducts of man but there is something extra discussed only in ethics and it is the traits of character. So according to this differentiation, the field of ethics is wider than jurisprudence.
Another difference might be considered in their purpose. There are special dos and don'ts in jurisprudence to safeguard man from hellfire. Thus in the case of a doubt about a ruling, one can appeal to the principle of exemption. But in ethics, man doesn’t care about punishment or rewards but what means to him is the perfection of the soul. So even if, there would be no hellfire still man had the motivation to practice ethical codes contrary to jurisprudential ones. In other words in jurisprudence man is considered as a servant that needs to obey his master but in ethics man looks forward to achieve perfection and closeness to Allah SWT.
Late Ayatollah Mahdavi Kanee believes that the approach is different i.e. when the value of man's conduct is taken into consideration not as a duty then it is ethical otherwise it becomes jurisprudential. Therefore if a specific action is rare to be done by someone it is not to be discussed in ethics, since such an action is not raised from the moral traits of the person and it's more like an accident but the very action can be studied in jurisprudence because it is subject to one of the five jurisprudential decrees anyway. (Mahdavi Kanee, 2009, p. 16)
But it seems even such an action can be studied and discussed in ethics as well because there is no why to accept this differentiation and we can ascribe value to that action as well. So if an action is to be practiced for once still its ethical aspect can be studied but according to the above mentioned view such an action is out of the realm of ethics and it is only to be evaluated in jurisprudence.
Even though it is really difficult to draw the exact borders between this two fields but for certain jurisprudence has a falling scale while ethics has a raising scale, i.e. in jurisprudence if the action with all its pre-requisites and conditions is done then it is accepted but man cannot do more than it and cannot practice something more than the duty. So when two people practice the obliged action like a daily prayer both is to be considered obedient and one cannot say my duty was more compulsory than the other's. Of course the action of one side might contain more value but this is to be discussed in ethics and concerns man's perfection.