Prohibition of quest, in addition to various narrations about the prohibition of quest into the privacy of others quoted from saints, indicates the importance of this issue for them. Prohibition of quest in an absolute form is not accepted by saints, and the scope and limit of this sanction include only secrets, defects, and personal and family slips that are not related to public interests; issues that depend on public goodwill and the preservation of Muslim systems are excluded from the prohibition of quest. Despite abundant discussions and narrations about the prohibition and exceptions of quest, the important issue of prohibition of quest as a juridical rule has been neglected in juridical literature and sources. However, discussion about the extension of the conditions and criteria of the juridical rule regarding the prohibition of quest is possible, and the importance, scope, and effects of prohibition of quest provide a foundation for its recognition. Recognizing prohibition of quest as a juridical rule can have important effects in social and legal dimensions. Therefore, in this paper, we aim to clarify two important issues: first, studying prohibition of quest as a juridical rule; and second, studying its effects and the legislator’s efforts to apply these Islamic rules in the criminal procedure system. Accordingly, in the present paper, using an analytical and descriptive method, the possibility of transforming this concept into a jurisprudential rule is examined, and its effects and consequences in Iran's criminal justice system are considered.