The mark known as the “trace of prostration” (sīmā) that is mentioned in the Quran is well established in Islam as being a physical blemish on the forehead. Such marks on the forehead are widespread in religious traditions, often denoting community membership and piety. The Quranic instance fits this tendency. The forelock is also a symbol associated with the forehead that the Quran mentions, although that piece of hair carries negative connotations. This common feature of a person's appearance can, in other cultural situations, denote membership and piety just like a mark on the forehead. The vocabulary of the Quran incorporates images from the past, although the evidence is too slight to allow origins to be traced; popular religious ideas and practices have many sources beyond scripture.
