The rule of obligation (Eghdam or Necessity Rule), according to one of the relatively common readings (for example: Al-ণ illƯ 1384 AH and Mostafavi 1412 AH) is responsible for regulating the relations of Shiites with non-Shiite Muslims (and according to a quote; all non-Shiites, both Muslims and non-Muslims) in cases where they believe a ruling opposes Shiite view and that ruling is in the interest of the Shiite, which in this case Shiite oblige that person to his/her non-Shiite view. This article, while examining the definition, scope and arguments of the jurisprudential rule of necessity (Eghdam), according to two elements: “ non-Shiite side” and “ benefit of the Shiite side” from the point of view of this famous reading, criticizes the arguments of this rule and with fundamental uncertainty in it, express some considerations including, the inference (conclusive) of multiple and unequal legal systems in domestic law, the separation of nationals to each other in private international law and incompatibility with the spirit of international custom and treaties in public international law. Although this reading of the rule is also opposed by contemporary jurists, the fundamental legal reasons presented in this article in criticizing this reading of the rule are different from those oppositions and are completely new. It goes without saying that some jurists, such as Mohammad Javad Fazel 2013 (1392 in the Solar Hijri calendar), have another reading of the obligatory rule that is more compatible with the rule of confirmatory and can seriously avoid the famous reading which is criticized in this article. The rule of obligation (Eghdam or Necessity Rule), as its name implies, requires, according to this famous reading, others (whether non-Shiites or non-Muslims) to adhere to the more difficult rules of their religion or sect. However, the rule of confirmatory is only the responsibility of approving or confirming different rulings of other religions or denominations, and it does not mention the obligation and element of harm or hardship for others.