Without any doubt, Islamic ethical teachings are supported by faith as the most fundamental religious teaching, yet, notability lies in a principal and really established view to faith and ethics and studying their capacity for correspondence for understanding ethical faith more exactly. It is, therefore, intended in the paper to give an exact meaning of faith, criticize some current views on sensational and emotional faith with regard to their impact on one`s characteristic and optional deeds and, infering fundamental element of faith from religious teachings, study the what and the why of commenting faith in a connection with ethical rationality. Finally, it is concluded that faith has a notable ground for the structure and content of Islamic ethical rationality.