Surah 2. Al-Baqara, Ayah 14

Lit., "their satans" (shayatin, pl. of shaytan). In accordance with ancient Arabic usage, this term often denotes people "who, through their insolent persistence in evildoing (tamarrud), have become like satans" (Zamakhshari): an interpretation of the above verse accepted by most of the commentators. However, the term shaytan - which is derived from the verb shatana, "he was [or "became"] remote [from all that is good and true]" (Lisan al-'Arab, Taj al-'Arus) - is often used in the Qur'an to describe the "satanic" (i.e., exceedingly evil) propensities in man's own soul, and especially all impulses which run counter to truth and morality (Raghib).

A deeper phase of insincerity is actual duplicity. But it never pays in the end. If we compare such a man to a trader, he loses in the bargain.