The present writing is trying to explain the essence of Faith in Mulla Sadra's philosophical thought. Firstly, I will deal with religious teachings that recall universally human beings to go toward belief which is introduced as the purpose of man's creation and positive responds to revelation. Then, the nature of faith will be discussed - whether it is a type of knowledge or it is merely a heartfelt confession. Finally, the paper will talk about degrees of faith and relationship between faith and intellectual perfection from one side and virtuous action and spiritual sates from another side.