William James, proposing the impact of non-noetice factors on the process of anquiring knowledge in his article " The will to Believe" led epistemologists to pay attention to this important point that perhaps achieving knowledge does not need only satisfying the epistemic standards, but since we obtain many beliefs under the influence of fears and hopes, loves and aversions, self-interests, etc., so sanctifying non-noetic realms of human being from vices and adorning them with virtues also affect on obtaining truth. What is discussed in this article is proposing the relation ship between one of the ethico-religious categories, ie., sin, and knowledge. The writer seeks to show how, in the late twenty years, epistemologists have paid attention to the discussion of the relation between non-epistemic and epistemic aspects of human existence, so that one can consider sin as an epistemological category.