From the Exsultet of the Easter Vigil evening ceremonies:
This is the night in which, destroying the chains of death, Christ arose victorious from the grave. For it profited us not to be born, if it had not profited us to be redeemed... O truly blessed night, which alone deserved to know the time and hour when Christ rose again from the tomb!Felix Culpa! O Happy Fault! The Latin expression felix culpa derives from the writings of St. Augustine regarding the Fall of Man, the source of original sin: “For God judged it better to bring good out of evil than not to permit any evil to exist.” (in Latin: Melius enim iudicavit de malis benefacere, quam mala nulla esse permittere.)
The phrase is sung annually in the Exsultet of the Easter Vigil: "O felix culpa quae talem et tantum meruit habere redemptorem," ("O happy fault that merited such and so great a Redeemer.")
The Angelic Doctor, St. Thomas Aquinas, cited this line when he explained that the principle whereby "God allows evils to happen in order to bring a greater good therefrom" underlies the causal relation between original sin and the Divine Redeemer's Incarnation, thus concluding that a higher state is not inhibited by sin. St. Ambrose also speaks of the fortunate ruin of Adam in the Garden of Eden in that his sin brought more good to humanity than if he had stayed perfectly innocent.