The necessity of the presence of an Imam is considered one of the most fundamental issues of Imamate. Islamic scholars, especially Shia scholars, have attempted to prove it with various approaches. Some have examined the existence of the Imam with an existential approach, emphasizing his existential position and influence on the system of creation. The content of this approach is mentioned in the narrations of Ahlul-Bayt under the titles "If it were not the Proof, the Earth would have perished" and "Trustworthy Hadiths." In the present article, an attempt is made to prove the existential position of the Imam in the system of creation by rational explanations of the mentioned narrations, and the necessity of the existence of the proof (Imam) for establishing and maintaining existence is clarified. These explanations are expressed in three philosophical, mystical, and theological ways. The existentialist approach to the existence of the Imam in the system of existence results in the Imam's authorship in creation and him as the ultimate purpose. Another fruit of this approach is the self-evident necessity of the existence of the Imam in the system of existence. In other words, the accurate "conception" of the Imam's position in the system of creation will be followed by "confirmation" of his existence.