The Enchiridion 100
100 The Will of God is Never Defeated, Though Much is Done that is Contrary to His Will PL 40, 278
These are the great works of the Lord, sought out according to all His pleasure, and so wisely sought out, that when the intelligent creation, both angelic and human, sinned, doing not His will but their own, He used the very will of the creature which was working in opposition to the Creator’s will as an instrument for carrying out His will, the supremely Good thus turning to good account even what is evil, to the condemnation of those whom in His justice He has predestined to punishment, and to the salvation of those whom in His mercy He has predestined to grace. For, as far as relates to their own consciousness, these creatures did what God wished not to be done: but in view of God’s omnipotence, they could in no wise effect their purpose. For in the very fact that they acted in opposition to His will, His will concerning them was fulfilled. And hence it is that “the works of the Lord are great, sought out according to all His pleasure,” because in a way unspeakably strange and wonderful, even what is done in opposition to His will does not defeat His will. For it would not be done did He not permit it (and of course His permission is not unwilling, but willing); nor would a Good Being permit evil to be done only that in His omnipotence He can turn evil into good.
Nihil fieri praeter voluntatem Dei, etiam dum fit contra ejus voluntatem. Haec sunt magna opera Domini, exquisita in omnes voluntates ejus : et tam sapienter exquisita, ut cum angelica et humana creatura peccasset, id est, non quod ille, sed quod voluit ipsa fecisset, etiam per eamdem creaturae voluntatem, qua factum est quod Creator noluit, impleret ipse quod voluit; bene utens et malis, tanquam summe bonus, ad eorum damnationem quos juste praedestinavit ad poenam, et ad eorum salutem quos benigne praedestinavit ad gratiam. Quantum enim ad ipsos attinet, quod Deus noluit fecerunt: quantum vero ad omnipotentiam Dei, nullo modo id efficere valuerunt. Hoc quippe ipso quod contra voluntatem fecerunt ejus, de ipsis facta est voluntas ejus. Propterea namque magna opera Domini, exquisita in omnes voluntates ejus; ut miro et ineffabili modo non fiat praeter ejus voluntatem, quod etiam contra ejus fit voluntatem. Quia non fieret, si non sineret: nec utique nolens sinit, sed volens; nec sineret bonus fieri male, nisi omnipotens et de malo facere posset bene.