And in falling, A'dam lost his creaturely status. To be a creature separated from God is to be non-human. For there is no humanity apart from one's dependence upon God. Humanity is contingent upon God. And in not being who we were created to be, we become inhuman toward one another.
Sin is the cause of our inhumanity.
Through the power of sin we lose our true identity. Through sin we find ourselves alienated, isolated from God and one another, wandering East of Eden, looking for the way home. The death and resurrection are seen as the primary redemptive acts. The cross and an empty tomb are certainly redemptive expressions of what Christ has done for us. Because Jesus came and lived and died and rose again as the fully human one.