Augustine held that God can command the rich to give to the poor. The poor can never demand from the rich; generosity is never owed.
To Augustine, we have two ways of acquiring justice: transcendent and immanent. Some describe imminent justice as legal justice and transcendent justice as religious justice. However, the Social Justice movement conflates the two.
No pre-society civilization ever existed. All sentient moral beings are by definition relational. Therefore, man's desire to love and be loved is the cause of civilization.