role of judge in finding the substantive rule of law

this is the obligation of judge in civil trial to finding substantive rule of law which is governing to a case in current resource of law. as an important role, it depends to have an accurate acknowledge about rule's resources and applying it in governing legal system. in iranian positive law we can see two rule of law concerning this obligation, first in principle 167 of constitution and second in article 3 of civil procedure law. in despite of accepting the civil law exigencies in our legal system, after the islamic revolution our country have chosen the islamic approach concerning judge's role. this approach is an area larger than civil law system in comparison. fitva and islamic reliable resources have been observed in the other side in despite of law's premier place between other resource.