Augustine's sick bride
Augustine (ch 16) imagines that the bride of Christ is ill and needs to be purged of her afflictions. The bride of Christ is a prostitute which he makes into a virgin bride by bearing her iniquity and giving her new life. Perhaps our differences are semantic on this point, but I think not.
The result of Augustine's error is the Catholic doctrines of Pugatory, purging of one's own sins through suffering, and indulgences. The view is that one must pay some sort of penalty for one's own sin.
Christ died for our sin. Any hint that his blood was insufficient to cleanse fully from sin suggests that Christ did not need to die. If any sin can be cleansed by our own work or suffering, then Jesus died in vain.
Christ makes his prostitute bride new through a new birth. He puts on a garment of skin/light אור which is his holiness.