Creed is the cornerstone of religious knowledge, as all moral values and individual and social behaviors depend on it. If the creed is sound, everything built upon it becomes sound, and if the creed is corrupted, everything relying on it becomes corrupted. Therefore, it is essential for us to identify accepted standards and well-studied criteria to distinguish the sound creed from the flawed one. In this article, we have explored several criteria and measures to differentiate truth from falsehood in beliefs. These include: the compatibility of the creed with sound innate human nature, its alignment with sound reasoning, the internal harmony and coherence among the elements of the creedal system, and the congruence of the creed with the desired practical and theoretical outcomes. Since this research relies on foundational principles and preliminary studies, we addressed-prior to outlining the criteria-the classifications of creedal issues and their objectives, paving the way for reaching the desired conclusion.