In this theoretical study, the symbol of the forbidden tree narrated in Quran (forbidden fruit in Bible) was analyzed and reinterpreted in the light of Terror Management Theory, a motivational theory of social psychology. The traditional interpretations made on the sembol of the forbidden tree that has significant implications for the origin of evil in the world, were thought to be unsatisfactory to demonstrate the ethical principle the forbidden tree conveyed. In addition, it was observed that what the forbidden tree symbol corresponded to in social life was not clearly explained. For that reason, a reinterpretation of the forbidden tree symbol in the light of contemporary knowledge was thought to be necessary. In the study, it was claimed that the reality symbolized with the forbidden tree was the desire to be immortal and all human attempts to achive immortality. Relying on the empirical findings obtained from terror management research, the ways how the desire for immortality and the attempts to be immortal engendered evil in the world was clarified.