Nafs (نَفْس) is an Arabic word occurring in the Quran, literally meaning "self", and has been translated as "psyche", "ego" or "soul".[2][3] The term is cognate with the Hebrew word nephesh, נֶפֶשׁ. In the Quran, the word nafs is used in both the individualistic (verse 2:48) and collective sense (verse 4:1), indicating that although humanity is united in possessing the positive qualities of a nafs, they are individually responsible for exercising the agencies of the "free will" that it provides them.
Much of the popular literature on nafs, however, is focused on the Sufi conceptions of the term located within the sadr (the chest). According to the Sufi philosophies, the nafs in its unrefined state is "the ego", which they consider to be the lowest dimension of a person's inward existence—his animal and satanic nature.[4] Nafs is an important concept in the Islamic tradition, especially within Sufism and the discipline of gnosis (irfan) in Shia Islam.