The Sunni and Shī'ah debate over whether the teachings of the Imāmah Shī'ah Imāmiyyah Ithnā 'Ashariyyah are included in the teachings of the Prophet Muhammad SAW cannot be avoided. Both saw the need for Imāmah as a substitute for the position of the prophet in managing religion and the world. However, there is a fundamental difference that cannot be tolerated. According to Ahl Sunnah wa al-jamā‘ah (the Sunnis), Imāmah is fardhu kifayah, while according to Shī'ah Imāmiyyah, it is one of the principles of faith which must be believed. This Shī'a belief also experienced a deadlock due to the polemic whether Imam al-Ḥasan al-'Ashkari had descendants or not. This deadlock was answered by them by bringing up a new concept in aqidah called Ghaybah. Therefore, the authors see the need to critically examine this concept of ghaybah, because it is the underlying foundation of the Imāmah that is believed. In addition to strengthening the faith of Muslims (the Sunnis), this study will also examine how strong the argument for the concept of ghaybah is. Through a study of library research type with a descriptive-critical analysis approach, it can be concluded that: First, the concept of ghaybah does not have a strong argumentative basis. Second, the figure of Imam Mahdi who they have believed in is only a fictitious figure. Third, the nature of Imam Mahdi's ghaybah contradicts the hadiths of the Prophet SAW and the statements of the Shī'ah scholars themselves