The “ original sin” , as a teaching, is one of the fundamental pillars of Polusian interpretation of Christianity that besides the justification of salvation, as a teaching, confirms the divinity of Jesus. Indeed, sin, salvation or grace and Christ divinity have a necessary and profound interrelationship to the extent that the denial or repudiation of one can create big challenges to the Polus’ transcendental system. The theologians and philosophers of Christianity like Saint Augustin, saint Anselm and Odo with the aim of better understanding sin, as a teaching, and providing defense against the critics’ opinions, besides preserving the framework of what Polus has expressed in his letters on the new testament, have tried to describe, interpret and justify his system of thought. Augustine, through inheritance, Anselm, through relying on human nature and Odo, through attributing referents to their antecedents, have tried to give a better explanation of the original sin, but none of them seems to be able to provide a dependable justification in this regard. The present paper intends to study and analyze the justifications provided by these three theologians.