Sufficient grace given even to those who fail
Thesis XXVII. They maintain that grace sufficient for doing good in this sense is given even to those who in fact fail to do the good work. God gives them aids by which they are able to act well, aids that furnish them proximate and complete power to do good, 'in first act', as the Schools put it.
What they lack is a further aid, required beforehand for the good work itself, which infallibly moves everyone who receives it to that work, and which God graciously grants to all who actually do good. These, accordingly, are said to have grace for doing good that is not only sufficient but efficacious too.
Latin
XXVII. Gratiam quae ea ratione sufficiat ad bene operandum, dari contendunt illis ipsis qui reapse a bono opere deficiunt. Nempe quia Deus dat illis auxilia, per quae bene agere possint, quaeque subministrant eis potentiam proximam & completam bene operandi, scilicet, ut loquuntur Scholae, in actu primo: etsi desit illis aliud auxilium, quod praeexigitur ad ipsum bonum opus, quodque omnes quibus datur infallibiliter ad tale opus movet, & benigne etiam conceditur omnibus illis qui actu bene operantur. Qui propterea dicuntur habere gratiam ad bene agendum, non solum sufficientem, sed etiam efficacem.