Scholars of any religion have always assumed the truth of that religion and sought to prove the superiority of their religion over other religions. They have presented numerous and various arguments and claims to prove not only the validity of their religion, but also the invalidity and deficiency of other religions. This is because they have believed that two religions cannot be rightful and true at the same time, so they have typically turned to religious exclusivism. The theory of religious pluralism, centered on John Hick, asserted the rightfulness of all religions and believed in religious pluralism, a theory whose traces can be seen in Frithjof Schuon’s and Mulla Sadra’s views. Schuon was a Muslim theologian who, in the school of traditionalism, believed in the unity of the essence of all religions by separating religions into essences and shells of religion; and Mulla Sadra was one of the Shiite philosopher who, through his comprehensive theory of salvation, considered the concepts of happiness and salvation to be graded and overarching concepts in all religions. Mulla Sadra and Schuon, influenced by Ibn Arabi’s mystical foundations and by presenting numerous arguments, considered all religions to be rightful and in accordance with truth. This paper expands and compares these two Muslim philosophers’ views using a comparative analysis and concludes that Mulla Sadra, who believed in the salvation of all human beings, was a Universalist, and Shuan, who sought to sprinkle truth on all the thoughts in the sphere of religion was an extremist pluralist.