Grace taken most widely includes nature itself
Thesis III. God gives us freely not only what surpasses nature: the goods of nature themselves we also have from his free kindness, without any merit of ours. So grace in its widest sense, as the same doctors observe, is not set against nature but includes nature itself, which is sometimes called grace because it is a free benefit God has given us for nothing.
This sense is common enough in ordinary speech, where we credit the gifts and advantages of nature to God's grace. In Scripture and in the schools it is very rare and little used.
There grace is usually confined to those benefits of God that go beyond the order of nature: they do not flow from nature and are not needed to make it what it is or to preserve it, but are added to it by God's free kindness.
Latin
III. Porro cum non solum quae naturam superant gratuito nobis a Deo donentur, sed ipsa naturae bona, absque ullis nostris meritis, ex gratuita Dei benignitate habeamus, idcirco gratia latissime sumpta, ut Doctores iidem observant, naturae non opponitur, sed naturam ipsam comprehendit: quae quandoque gratiae nomine designatur, propterea quod est gratuitum quoddam Dei beneficium, gratis nobis a Deo collatum. Verum haec acceptio gratiae est quidem frequens in usu communi, in quo naturae dotes atque commoda gratiae divinae ascribere solemus, sed in scripturis & Scholis rarissima, & parum usitata est. Plerunque enim ibi gratia restringitur ad illa Dei beneficia quae naturae ordinem excedunt, neque ex natura fluunt, aut ad eam constituendam & conservandam necessaria sunt, sed ex gratuita Dei benignitate ipsi superaddita.