In Christianity, 'sin' is an immoral act considered to be a transgression of divine law. The doctrine of sin is central to the Christian faith, since its basic message is about redemption in Christ. Hamartiology, a branch of Christian theology which is the study of sin, describes sin as an act of offence against God by despising his persons and Christian biblical law, and by injuring others. Christian hamartiology is closely related to concepts of natural law, moral theology and Christian ethics. According to Augustine of Hippo (354–430) sin is "a word, deed, or desire in opposition to the eternal law of God," or as scripture states, "sin is the transgression of the law." Among some scholars, sin is understood mostly as legal infraction or contract violation of non-binding philosophical frameworks and perspectives of Christian ethics, and so salvation tends to be viewed in legal terms. Other Christian scholars understand sin to be fundamentally relational—a loss of love for the Christian God and an elevation of self-love ("concupiscence", in this sense), as was later propounded by Augustine in his debate with the Pelagians. As with the legal definition of sin, this definition also affects the understanding of Christian grace and salvation, which are thus viewed in relational terms. Hamartiology (from Greek: ἁμαρτία, hamartia, "a departure fr. either human or divine standards of uprightness" and -λογια, -logia, "study") The first use of sin as a noun in the Old Testament is of "sin is crouching at your door; it desires to have you, but you must rule over it" waiting to be mastered by Cain, a form of literary theriomorphism. Synthesis: bulletin du Comité national de littérature comparée / Comitetul Național pentru Literatură Comparată, Institutul de Istorie și Teorie Literară "G. Călinescu." – 2002 "Sin is personified as (an animal?) which "crouches" at the door of Cain (Gen 4:7).